INSM1 Is a Highly Specific Marker of Neuroendocrine Differentiation in Primary Neoplasms of the Gastrointestinal Tract, Appendix, and Pancreas

OBJECTIVES

INSM1 has been described as a sensitive and specific neuroendocrine marker. This study aims to compare INSM1 with traditional neuroendocrine markers in gastrointestinal neuroendocrine neoplasms.

METHODS

Retrospective review (2008-2018) was used to retrieve paraffin-embedded tissue from 110 gastrointestinal neuroendocrine neoplasms and controls that was subsequently stained with INSM1, synaptophysin, chromogranin, CD56, and Ki-67.

RESULTS

INSM1 was positive in 16 of 17 (94.1%) gastric, 17 of 18 (94.4%) pancreatic, 13 of 18 (72.2%) small bowel, 17 of 21 (81.0%) colonic, and 26 of 36 (72.2%) appendiceal tumors. INSM1 was positive in 58 of 70 (82.9%) well-differentiated neuroendocrine tumors, 17 of 20 (85.0%) poorly differentiated neuroendocrine carcinomas, 8 of 11 (72.7%) low-grade goblet cell adenocarcinomas (grade 1), and 6 of 9 (66.7%) high-grade goblet cell adenocarcinomas (grade 2/3). INSM1 sensitivity for neuroendocrine neoplasms (80.9%) was less than that of synaptophysin (99.1%), chromogranin (88%), and CD56 (95.3%); specificity was higher (95.7% vs 86.0%, 87.3%, and 86.0%, respectively).

CONCLUSIONS

INSM1 is a useful marker of neuroendocrine differentiation in gastrointestinal neuroendocrine and mixed neuroendocrine neoplasms. Compared with traditional neuroendocrine markers, INSM1 is less sensitive but more specific.

SATB2 is a supportive marker for the differentiation of a primary mucinous tumor of the ovary and an ovarian metastasis of a low-grade appendiceal mucinous neoplasm (LAMN): A series of seven cases

The differentiation between a primary mucinous ovarian neoplasm and an extra-ovarian metastasis in the ovary is often challenging in the histopathologic practice. Among various ovarian metastases from the gastro-intestinal tract the low-grade appendiceal mucinous neoplasm (LAMN) is an important differential diagnosis to consider particularly in case of pseudomyxoma peritonei. A newly recognized marker in the routine diagnostic of a mucinous neoplasm in the ovary is SATB2 (Special AT-rich sequence-binding protein 2). The expression of SATB2 is, within cells of epithelial lineages, mainly restricted to the lower gastro-intestinal tract, indicating colorectal or appendiceal cancer origin. We report seven cases of LAMN, which clinically became apparent due to ovarian metastases in context of pseudomyxoma peritonei or at least small foci of peritoneal tumor spread. An immunohistochemical marker-panel including SATB2, CDX2, CK20, CK7, PAX8, ER and PR revealed a strong expression of SATB2 in all seven cases. On the contrary SATB2-negativity could be demonstrated in the 40 cases of mucinous borderline tumors and primary mucinous carcinomas of the ovary. The histopathologic tentative diagnosis of an ovarian metastasis of LAMN could be confirmed in the findings of the Appendix in six of seven cases. This report supports SATB2 as an additional diagnostic marker for the diagnosis of an ovarian manifestation of LAMN.

CK19 and CD99 Immunoexpression Profile in Goblet Cell (Mucin-Producing Neuroendocrine Tumors) and Classical Carcinoids of the Vermiform Appendix

The immunoexpression of CK19 recently has been identified as a marker of poor prognosis in pancreatic endocrine tumors and hepatocellular carcinoma. Conversely, the loss of expression of CD99 has been suggested to play a role in the tumorigenesis and dedifferentiation and is associated with poor outcome in some malignancies. The purpose of this study was to explore CK19 and CD99 immunostaining in mucin-producing neuroendocrine (goblet cell) and classical carcinoids of the appendix. Eighteen goblet cell carcinoids (GCCs) and 20 classic carcinoids were stained with CK19, CD99, and Ki-67, and these results were correlated with known pathological features of aggression: extent of invasion, mitoses, necrosis, and histological pattern. All 18 GCCs were CK19 strongly positive, whereas 16/20 classic carcinoids were also CK19 positive. Fourteen of 18 GCCs and 14/20 classic carcinoids were CD99 positive. CK19/CD99 immunoexpression did not correlate with extent of tumor invasion and mesoappendiceal extension, mitotic activity, Ki-67 labeling index, presence of extracellular mucinous pools dissecting muscle, and angiolymphatic and perineural/neural invasion. There is no difference in the immunostaining for CK19 and CD99 between GCCs and classic carcinoids, and both types of neuroendocrine tumor show the same extent of expression of both markers.

A comprehensive expression analysis of mucins in appendiceal carcinoma in a multicenter study: MUC3 is a novel prognostic factor

BACKGROUND

Mucins are implicated in survival in various cancers, but there have been no report addressed on survival in appendiceal carcinoma, an uncommon disease with different clinical and pathological features from those of other colon cancers. We aimed to investigate the clinical implications of expression of mucins in appendiceal carcinoma.

METHODS

Expression profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC6, MUC16 and MUC17 in cancer tissue were examined by immunohistochemistry in 108 cases of surgically resected appendiceal carcinoma.

RESULTS

The following relationships of mucins with clinicopathologic factors were identified: MUC1 with positive lymphatic invasion (p = 0.036); MUC2 with histological type (mucinous carcinoma, p<0.001), superficial invasion depth (p = 0.007), negative venous invasion (p = 0.003), and curative resection (p = 0.019); MUC3 with non-curative resection (p = 0.017); MUC5AC with histological type (mucinous carcinoma, p = 0.002), negative lymphatic invasion (p = 0.021), and negative venous invasion (p = 0.022); and MUC16 with positive lymph node metastasis (p = 0.035), positive venous invasion (p<0.05), and non-curative resection (p = 0.035). A poor prognosis was related to positive lymph node metastasis (p = 0.04), positive lymphatic invasion (p = 0.02), positive venous invasion (p<0.001), non-curative resection (p<0.001), and positive expression of MUC3 (p = 0.004). In multivariate analysis, positive venous invasion (HR: 6.93, 95% CI: 1.93-24.96, p = 0.003), non-curative resection (HR: 10.19, 95% CI: 3.05-34.07, p<0.001) and positive MUC3 expression (HR: 3.37, 95% CI: 1.13-10.03, p = 0.03) were identified as significant independent prognostic factors in patients with appendiceal carcinoma.

CONCLUSIONS

Expression of MUC3 in appendiceal carcinoma is an independent factor for poor prognosis and a useful predictor of outcome in patients with appendiceal carcinoma after surgery.

Pre-operative tumour marker status predicts recurrence and survival after complete cytoreduction and hyperthermic intraperitoneal chemotherapy for appendiceal Pseudomyxoma Peritonei: Analysis of 519 patients

BACKGROUND

Cytoreductive surgery (CRS) combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is the optimal treatment for Pseudomyxoma Peritonei (PMP). Despite treatment, disease often recurs and may not be amenable to further CRS. Clinical experience suggests a spectrum of disease which may correlate with tumour marker levels. The aim of this study was to analyse the influence of markers on recurrence and survival.

METHODS

The details of all patients undergoing surgery for PMP of appendiceal origin at a national centre for peritoneal malignancy were recorded in a dedicated prospective database. The data on all patients who had CRS and HIPEC between March 1994 and January 2012 was analysed and recurrence and survival correlated with pre-operative levels of CEA, CA-125 and CA19-9.

RESULTS

Overall, 519 (69%) of 752 consecutive patients, underwent complete CRS and HIPEC. The median (range) age was 56 (20-82) years with 342/519 (66%) females. The mean overall (OS) and disease free survival (DFS) in the 131/519 patients who had normal preoperative tumour markers was 168 (128-207) and 125 (114-136) months respectively, significantly higher when compared with the 109/519 (21%) who had all three tumour markers elevated (OS of 65 (42-88) and DFS of 55 (41-70) months respectively) (P = 0.002).

CONCLUSIONS

Elevated tumour markers predict an increased risk of recurrence and reduced survival after complete CRS. This may reflect cell biology in low grade tumours and is an independent prognostic feature. Further analysis may help to select patients for post-operative chemotherapy, second look procedures or stratification of follow up.

Goblet cell carcinoid of the vermiform appendix - a case report

Goblet cell carcinoid (GCC) is a rare neuroendocrine tumor of the vermiform appendix with uncertain clinical behavior. It was first described by Gagné and Subbuswamy in 1969 and 1974, respectively. The tumor occurs almost exclusively in the vermiform appendix. We present a case of a 60-year-old female, who was referred to the Bielanski Hospital with signs and symptoms of acute appendicitis. Microscopic examination of the appendix showed features of acute appendicitis, however scattered groups of cells with clear cytoplasm as well as strands of single cells with no evidence of atypia were seen. The patient underwent a right hemicolectomy due to the diagnosis of GCC.

Clear cell carcinoid of the appendix: an uncommon variant of lipid-rich neuroendocrine tumor with a broad differential diagnosis

The designation of clear cell/lipid-rich refers to an unusual variant of neuroendocrine tumor ("carcinoid") described in several organs, but only recently observed in the appendix. In this study, we report the morphologic, immunohistochemical, and ultrastructural features of an incidentally discovered appendiceal clear cell/lipid-rich carcinoid in a 32-year-old man without any evidence of von Hippel-Lindau disease. Differential diagnosis with mimicking neoplastic and non-tumor lesions, epidemiology, and clinical behavior of this exceedingly rare variant of carcinoid of the appendix are also discussed.

[Appendicular metastatic involvement in breast cancer]

The paper describes a case of appendicular metastatic involvement in breast cancer. The 60-year-old female patient developed the signs of acute appendicitis 18 years after detection of primary tumor; after appendectomy the intraoperative appendular specimens exhibited trains of tumor cells that infiltrated the mid- and lower muscle layer third. Immunohistochemical study revealed a moderate expression of Er and Pgr receptors (150 H scores), a positive reaction with EMA, K7, K6, and lactoalbumin The authors review the data available in the literature on the specific features of metastatic spread into the appendix and on management tactics in these patients.

Ovarian Metastases of Appendiceal Tumors With Goblet Cell Carcinoidlike and Signet Ring Cell Patterns

Synchronous and metachronous ovarian and appendiceal mucinous tumors are often the subject of diagnostic consultations in gynecologic pathology practices to address whether the tumors are independent neoplasms or related as primary and metastasis. Those with goblet cell carcinoidlike patterns have not been extensively evaluated in a large series. Clinicopathologic features of 30 cases were examined. All patients presented with signs or symptoms related to a pelvic/adnexal or abdominal mass. The ovarian tumors were bilateral in 25 of 28 cases with data on both ovaries and were typically large (mean/median: 14 cm, range: 4.5 to 24.0 cm). The appendices were often firm or thickened but usually did not have a discrete measurable tumor and were not notably enlarged; microscopically, transmural invasion was present in all of them. The ovarian and appendiceal tumors exhibited a variety of patterns of differentiation, including signet ring cell and glandular, with all displaying some goblet cell carcinoidlike patterns (nests, islands, cords, or cryptlike tubules with goblet cells); teratomatous elements were not identified in any ovarian tumors. Chromogranin was expressed in 7 of 19 ovarian tumors (mean/median: 6.3%/0%; range: 0% to 20%) and synaptophysin was expressed in 4 of 18 of these (mean/median: 7.8%/0%; range: 0% to 90%). Chromogranin was expressed in 6 of 16 appendiceal tumors (mean/median: 11.9%/0%; range: 0% to 70%) and synaptophysin was expressed in 6 of 15 of these (mean/median: 16.7%/0%; range: 0% to 90%). Follow-up was available for 25 patients: 17 died of disease at intervals ranging from 4 to 47 months (mean/median: 18/16) and 8 were alive with disease at 1 to 25 months (mean/median: 11/10); median survival was 19 months and the 1-year and 2-year survival rates were 63% and 34%, respectively. The clinicopathologic features of these ovarian tumors indicate they should be labeled as metastatic appendiceal adenocarcinomas rather than as goblet cell carcinoid tumors both to reflect their behavior and help distinguish them from the rare true primary ovarian goblet cell carcinoid tumors. As the ovarian tumors have appreciable components of signet ring cells they qualify as Krukenberg tumors. In cases in which the primary tumor is not already evident, their "goblet cell carcinoidlike" patterns should direct attention to the appendix as a possible source.

MUC2, MUC5AC and MUC5B in the mucus of a patient with pseudomyxoma peritonei: biochemical and immunohistochemical study

A 58-year-old man with a 1 year history of progressive abdominal distension underwent a laparotomy for pseudomyxoma peritonei. The mucin was identified and characterized in the present study. Approximately 6 L of crude mucus in the sol (highly viscous) and gel (semisolid) phases was obtained from the patient's peritoneal cavity. The sol material was briefly homogenized followed by slow stirring at dilutions of up to 1:10 with 6 mol/L guanidinium chloride and proteolytic inhibitors for periods of up to 48 h. Preparative and analytical gel filtration on Sepharose 2B showed some PAS-positive material eluting in the void volume accompanied by equal or larger amounts of protein in the void and included volumes of the columns. Sodium dodecylsulfate-polyacrylamide gel electrophoresis of purified mucin on a 4-20% gradient gel showed PAS-positive material on the top of the running gel and a distinct smaller-sized species of mucin of higher electrophoretic mobility with background material in between the large and small mucin. Western blot (confirmed by immunohistochemical analysis) after agarose gel electrophoresis showed the presence of MUC2, MUC5AC and MUC5B in the mucus. There was no MUC1, MUC1core or MUC6 in the tissue. Histopathological examination confirmed a mucinous appendicular adenocarcinoma. Histology showed the mucin to be predominantly of the sulfated and non-sulfated acidic type. Serine, threonine and proline comprised 21.6% of the total amino acid composition of the sample. The viscous nature of the material is due to the presence of three gel-forming mucins and possibly to its high content of protein.

Mucinous tumor of uncertain malignant potential in a perforated appendectomy specimen. A case report

Mucinous tumors of uncertain malignant potential are rare; there are only occasional reports. We report the first case where the tumor was identified incidentally following resection of a perforated appendicitis. There was no previous history to suggest for a mucinous tumor. No other abnormalities were found at surgery. Treatment included right hemicolectomy, considering the risk of residual or metastatic disease of about 10%. The patient is alive and well twelve months after resection of the tumor.

Cytokeratins 7 and 20 immunoexpression profile in goblet cell and classical carcinoids of appendix

Goblet cell carcinoid (GCC) of the vermiform appendix is an uncommon neoplasm and its histogenesis is controversial. Whether GCC represents a morphological variant of classical appendiceal carcinoid or a mucin-producing adenocarcinoma is still conjectural. Little is known about the immunohistochemical expression of cytokeratins 7 (CK7) and 20 (CK20) in appendiceal neuroendocrine tumors. In this study, we compared the expression of CK7 and CK20 in 17 cases of appendiceal GCC and 25 cases of classical carcinoid. The tumors were also evaluated for Ki-67 proliferation index, mitotic activity, tumor necrosis, extracellular pools of mucin, obvious intestinal type adenocarcinomatous foci, angiolymphatic permeation, perineural/neural infiltration, and the depth of invasion of the appendix wall. Mesoappendiceal extension was present in 14 of 17 (82.3%) cases of GCC, whereas angiolymphatic and perineural/intraaneural involvement were found in 10 of 17 (58.8%) and 14 of 17 (82.3%) cases, respectively. The mitotic count ranged from 0 per 10 high power fields to 6 per 10 high power fields, with an average of 1.4 per 10 high power fields. Necrosis was not seen in any case and pools of extravasated mucin were present in 5 of 17 (29.4%) cases. Immunohistochemically, all 17 (100%) of GCC exhibited strong and diffuse immunopositivity for CK20, whereas expression of CK7 was present in 12 cases (70.5%), ranging from 5 to 50% of tumor cells being labeled. The Ki-67 labeling index ranged from 0 to 75% and showed no correlation to mitotic activity, angiolymphatic invasion or perineural/intraneural permeation. On the other hand, 25 cases of classical carcinoid tumors were consistently negative for CK7; however, 4 cases (16%) showed immunolabeling for CK20 in 25-50% of the tumor cells. The Ki-67 labeling index in classical carcinoids ranged from 0 to 5%. This study shows that in addition to the morphological differences, GCC (CK7/CK20-positive) and classical carcinoid (CK7/CK20-negative) differ in their expression of CK7 and CK20. In addition, GCC shows the same CK7/CK20 immunoexpression as colorectal adenocarcinoma. Goblet cell carcinoid should be regarded as a crypt cell or an amphicrine carcinoma rather than a variant of carcinoid tumor, a lesion that has benign connotations.

CDX-2 expression in pseudomyxoma peritonei: a clinicopathological study of 42 cases

AIMS

CDX-2 is a highly sensitive and specific marker of intestinal epithelial cells and their neoplastic counterparts. CDX-2 status in pseudomyxoma peritonei (PMP) has been barely reported. The aim of this study was to investigate the clinicopathological features of 42 cases of PMP with a special emphasis on CDX-2.

METHODS AND RESULTS

All patients were treated by cytoreduction. Immunohistochemistry was performed for CDX-2, MUC-2, MUC-5AC, cytokeratin (CK) 7 and CK20. Statistical correlation was evaluated for age, sex, completeness of cytoreduction and histological subtype with overall and progression-free survival (OS and PFS). PMP consisted of 32 cases of disseminated peritoneal adenomucinosis and 10 cases of peritoneal mucinous carcinomatosis. The appendix evaluated in 25 cases showed two mucinous adenocarcinomas and 21 low-grade appendiceal mucinous neoplasms. CDX-2 was diffusely positive in 40 cases, with the remaining two cases being focally positive. All cases demonstrated diffuse reactions to CK20 and MUC-2, and variable reactions to MUC-5AC, while CK7 was variably positive in 38 cases. Five-year OS was 97%. Histological type was significantly correlated with PFS (P=0.02).

CONCLUSIONS

CDX-2 is diffusely and strongly positive in PMP. This is a useful marker to confirm an appendiceal origin of PMP, particularly when used in conjunction with CK7, CK20, MUC-2 and MUC-5AC.

Cushing's syndrome caused by an occult source: difficulties in diagnosis and management

BACKGROUND

A 24-year-old woman presented with a 12.5 kg weight gain over 6 months (mostly abdominal), hirsutism, acne, ankle edema, polydipsia, nocturia, back pain, pigmentation, poor libido and lightened menses to our hospital in May 1986. She had been treated for the previous 2 years with furosemide and spironolactone for peripheral edema, and had stopped the combined oral contraceptive 2 months previously. She did not take tobacco, recreational drugs or alcohol. Upon physical examination she was grossly Cushingoid with florid clinical manifestations.

INVESTIGATIONS

Serum potassium and bicarbonate, circadian rhythm of cortisol, low-dose and high-dose dexamethasone suppression tests, plasma adrenocorticotropic hormone (ACTH), corticotropin releasing-hormone stimulation test, CT scan of the pituitary, plain chest radiology, CT scan of the chest and abdomen, trans-sphenoidal pituitary biopsy and histology, CT scan and MRI of the thorax, MRI of the pituitary, octreotide scintigraphy, gastroscopy, colonoscopy, gut peptides, tumor markers, urine 5-hydroxyl-indole-acetic acid, resection, histology, immunocytochemistry and in situ hybridization.

DIAGNOSIS

Occult ectopic ACTH syndrome from a presumed appendiceal neuroendocrine tumor. The tumor was only identified some 20 years from initial presentation.

MANAGEMENT

Adrenolytic therapy before bilateral adrenalectomy to cure Cushing's syndrome, glucocorticoid and mineralocorticoid replacement therapy, and then repeated surveillance over 20 years to locate the ectopic source of ACTH. This was finally identified by CT scan and excised at laparotomy.

Expression of the Intestinal Transcription Factor CDX2 in Carcinoid Tumors Is a Marker of Midgut Origin

Context.—Carcinoid tumors are classified according to their site of origin into foregut, midgut, or hindgut carcinoids, which have different presentations and prognosis. The intestinal transcription factor CDX2 has been found to be expressed in most intestinal adenocarcinomas but in less than one half of the gastrointestinal carcinoids according to 1 study.

Objective.—To determine whether CDX2 expression in carcinoid tumors varies by the site of origin and whether CDX2 expression is retained in metastatic disease.

Design.—Sections of formalin-fixed and paraffin-embedded tissue from 36 primary carcinoid tumors and 5 cases of metastatic carcinoid to the liver were immunohistochemically stained for CDX2. The percent of cells with nuclear immunoreactivity and the intensity of staining were assessed.

Results.—All 18 foregut carcinoids (10 pulmonary and 8 gastric) were negative (0%) for CDX2. All 11 midgut carcinoids (100%) were positive for CDX2 with moderate to strong staining in more than 50% of the cells. Only 2 (29%) of 7 of hindgut carcinoids were CDX2-positive with the 2 positive cases showing weak to moderate staining intensity in less than 10% of the cells. Expression of CDX2 in more than 50% of tumor cells was seen only in midgut carcinoids (P &lt; .001). CDX2 expression in metastatic tumors was consistent with the site of origin.

Conclusions.—Midgut carcinoid tumors and their metastases are distinct from foregut and hindgut carcinoids in that they express high levels of CDX2. Additional studies are needed to determine whether CDX2 immunostaining may be helpful in determining the primary site of metastatic carcinoid tumors of unknown origin.

Immunohistochemical expressions of cytokeratins, mucin core proteins, p53, and neuroendocrine cell markers in epithelial neoplasm of appendix

Epithelial neoplasms of appendix are infrequent, and their pathological features are not fully characterized. We collected 33 cases of appendiceal tumors and examined immunohistochemically the expression of cytokeratins (CK, CK7, and CK20), mucin core protein (MUC1, MUC2, MUC5AC, and MUC6), E-cadherin, chromogranin A, and p53 protein. Gene analysis of TP53 was also conducted on exons 5 to 8. Clinically, mucinous tumors were predominant in females. Immunohistochemically, all the tumors expressed CK20, whereas CK7 was positive in one third of the cases. Similarly, MUC2 was expressed in all the tumors, whereas MUC1 and MUC5AC were detected in about a half of the cases. Although chromogranin A-positive cells are generally sparse in normal appendix, they were more common in mucinous tumors than in nonmucinous tumors. Contrary to the previous data reported (Mod Pathol 2002;15:599-605), mucinous carcinoma exhibited a higher frequency of p53-positive cells (mean 29%) compared with mucinous adenoma (2.8%) (P < .001), whereas nonmucinous tumors showed high levels of p53-positive cells to similar extent (51%-67%) in both adenoma and carcinoma. The high expression of p53 protein coincided with the presence of mutations in multiple sites of TP53 gene in mucinous tumors. This is the first report that characterized the immunophenotypic profile of appendiceal epithelial neoplasms with an emphasis of a higher frequency of p53 positivity in mucinous carcinoma cases compared with mucinous adenoma in the appendix.

Immunohistochemistry for estrogen and progesterone receptors in the distinction of primary and metastatic mucinous tumors in the ovary: an analysis of 124 cases

Estrogen (ER) and progesterone receptor (PR) expression in primary ovarian mucinous tumors and the utility of these markers for distinguishing metastatic mucinous carcinomas in the ovary from primary ovarian mucinous tumors have not been extensively investigated. Immunohistochemical studies were performed on 124 mucinous tumors, including 52 primary ovarian tumors (30 atypical proliferative (borderline) mucinous tumors of gastrointestinal type, 11 atypical proliferative (borderline) mucinous tumors of seromucinous (endocervical-like) type, and 11 invasive mucinous carcinomas of usual (gastrointestinal) type) and 72 metastatic mucinous carcinomas in the ovary (primary sites: colorectum (24), pancreas (13), endocervix (eight), stomach (four), gallbladder/bile duct (four), appendix (four), and unknown (15)). All atypical proliferative mucinous tumors of gastrointestinal type, primary ovarian mucinous carcinomas, and metastatic mucinous carcinomas were negative for ER and PR with the exception of three metastatic endocervical adenocarcinomas which exhibited only weak expression of ER without PR. All atypical proliferative mucinous tumors of seromucinous type expressed ER to some degree and seven had some expression of PR. Immunohistochemical assessment of hormone receptor expression is of no value in distinguishing the common types of primary ovarian mucinous tumors (atypical proliferative mucinous tumors of gastrointestinal type and mucinous carcinomas of usual type) from the vast majority of mucinous carcinomas metastatic to the ovary. The above observations on hormone receptor expression in primary ovarian mucinous tumors support the concept that atypical proliferative (borderline) mucinous tumors of gastrointestinal and seromucinous (endocervical-like) types are distinctive tumors.

High expression of RELP (Reg IV) in neoplastic goblet cells of appendiceal mucinous cystadenoma and pseudomyxoma peritonei

The regenerating protein (Reg)-like protein (RELP, also known as Reg IV) is a recently characterized fourth member of the human Reg protein family. The Reg proteins are small, about 20-kD-sized, secretory proteins of C-lectin type. The previously known Reg proteins have been functionally implicated in regeneration, proliferation, and differentiation of the pancreas, liver, and gastrointestinal mucosa. To study the tissue expression of RELP, we raised a monoclonal antibody to RELP. By immunohistochemistry and in situ hybridization, we found a robust de novo expression of RELP in the neoplastic goblet cells of appendiceal mucinous cystadenomas and in the epithelial implants of pseudomyxoma peritonei (PMP). Our findings indicate that RELP serves as a marker for appendiceal mucinous cystadenomas and PMP, and that RELP may contribute to the pathogenesis of these disorders.

RASSF1A promoter methylation and 3p21.3 loss of heterozygosity are features of foregut, but not midgut and hindgut, malignant endocrine tumours

The Ras-association domain family 1A (RASSF1A) tumour suppressor gene is inactivated in a variety of solid tumours, usually by epigenetic silencing of the promoter and/or allelic loss of its locus at 3p21.3. RASSF1A induces cell cycle arrest through inhibition of cyclin D1 accumulation. In this work, 62 endocrine tumours from different sites in the gut were investigated for methylation of the RASSF1A promoter using the polymerase chain reaction, the presence of 3p21.3 deletions by loss of heterozygosity analysis, and cyclin D1 expression by immunohistochemistry. Methylation was found in 20/62 (32%) cases and was restricted to foregut tumours; deletion at 3p21.3 was found in 15/58 (26%) informative cases and restricted to malignant foregut tumours; cyclin D1 hyper-expression was found in 31/58 (53%) cases and correlated with RASSF1A methylation. Our data suggest that RASSF1A is involved in the development of endocrine tumours derived from the foregut only, and that the presence of both RASSF1A methylation and 3p21.3 deletion is associated with malignancy. These results may provide a rationale for foregut-targeted therapy for aggressive endocrine carcinomas entailing the use of demethylating agents.

Hypoxia and Photofrin uptake in the intraperitoneal carcinomatosis and sarcomatosis of photodynamic therapy patients

PURPOSE

Response to photodynamic therapy depends on adequate tumor oxygenation as well as sufficient accumulation of photosensitizer in the tumor. The goal of this study was to investigate the presence of hypoxia and retention of the photosensitizer Photofrin in the tumors of patients with intra-abdominal carcinomatosis or sarcomatosis.

EXPERIMENTAL DESIGN

Tumor nodules from 10 patients were studied. In nine of these patients, hypoxia was identified in histological sections of biopsied tumor after administration of the hypoxia marker 2-(2-nitroimidazol-1[H]-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5). In separate tumor nodules from 10 patients, Photofrin uptake was measured by fluorescence after tissue solubilization.

RESULTS

Hypoxia existed in the tumors of five patients, with three of these patients demonstrating at least one severely hypoxic nodule. Physiological levels of oxygen were present in the tumors of four patients. An association between tumor size and hypoxia was not evident because some tumor nodules as small as approximately 2 mm in diameter were severely hypoxic. However, even these tumor nodules contained vascular networks. Three patients with severely hypoxic tumor nodules exhibited moderate levels of Photofrin uptake of 3.9 +/- 0.4 to 3.9 +/- 0.5 ng/mg (mean +/- SE). The four patients with tumors of physiological oxygenation did not consistently exhibit high tumor concentrations of Photofrin: mean +/- SE drug uptake among these patients ranged from 0.6 +/- 0.8 to 5.8 +/- 0.5 ng/mg.

CONCLUSIONS

Carcinomatosis or sarcomatosis of the i.p. cavity may exhibit severe tumor hypoxia. Photofrin accumulation in tumors varied by a factor of approximately 10x among all patients, and, on average, those with severe hypoxia in at least one nodule did not demonstrate poor Photofrin uptake in separate tumor samples. These data emphasize the need for reconsideration of the generally accepted paradigm of small tumor size, good oxygenation, and good drug delivery because this may vary on an individual tumor basis.

Mixed carcinoid and adenocarcinoma of the appendix: report of 4 cases with immunohistochemical studies and a review of the literature

Four cases of mixed carcinoid and adenocarcinoma of the appendix were reported. All cases presented with a dominant cecal-appendiceal tumor mass and local metastasis. Two patients had multiple peritoneal implants mimicking primary peritoneal serous adenocarcinoma or carcinomatosis. Histopathologic features of the tumors are similar, with infiltrating microglandular and cribriform patterns of tumor nests, and variable numbers of goblet cells. A literature review of "goblet cell carcinoid" that included nonlocalized cases revealed a significant percentage (>14%) of tumor-associated death, in contrast to the classic carcinoid tumor. Immunohistochemical stains were helpful to separate these tumors from carcinoid tumors and primary peritoneal serous adenocarcinoma. Mixed carcinoid and adenocarcinomas were cytokeratin (CK)-20 positive, and negative or weakly positive for chromogranin A and synaptophysin. Carcinoid tumors were CK20 negative and diffusely positive for chromogranin A and synaptophysin. Peritoneal serous adenocarcinomas were CK20 negative. These cases were clinically aggressive, and 1 patient had multiple recurrences and responded partially to chemotherapy.

Defective mismatch repair in the pathogenesis of low-grade appendiceal mucinous neoplasms and adenocarcinomas

Defective DNA mismatch repair has been proposed as a second pathway for colonic carcinogenesis, particularly in tumors arising in the right colon. We investigated whether tumors arising in the appendix are associated with defective DNA mismatch repair using immunohistochemistry for mismatch repair enzymes hMLH-1, hMSH-2, hMSH-6, and hPMS-2. These immunoassays have been shown to be highly sensitive and specific for defective DNA mismatch repair in sporadic and familial adenocarcinomas. Sporadic adenocarcinomas with defective DNA mismatch repair essentially always show loss of hMLH-1, while loss of hMSH-2, hMSH-6, or hPMS-2 is almost always due to germline mutation. In all, 35 cases of appendiceal epithelial neoplasms were evaluated, comprising 18 low-grade appendiceal mucinous neoplasms confined to the appendix; eight low-grade appendiceal mucinous neoplasms with extra-appendiceal spread (five peritoneum and ovaries, two peritoneum, one ovaries only); and nine invasive adenocarcinomas (three with metastatic disease). All immunohistochemical slides were reviewed by two pathologists. One (11%) invasive adenocarcinoma showed absent expression of hMSH-2 and hMSH-6, but preserved hMLH-1 and hPMS-2 expression. This case was a 26-year-old female with a history of synovial sarcoma who presented with acute appendicitis and appendiceal perforation (median age for other invasive carcinomas, 62 years; range 38-76 years). The appendiceal tumor was a moderately differentiated, colonic-type adenocarcinoma without significant extracellular mucin or tumor-infiltrating lymphocytes. The remaining invasive carcinomas and low-grade appendiceal mucinous neoplasms demonstrated preserved expression of all mismatch repair enzymes, including the seven cases in which extra-appendiceal tumor was also evaluated. We conclude that defective DNA mismatch repair does not play a role in the pathogenesis of low-grade appendiceal mucinous neoplasms. Defective DNA mismatch was found in 11% of invasive carcinomas, likely due to a germline mutation. These findings suggest that sporadic appendiceal neoplasia rarely arises through the defective DNA mismatch repair (mutator) pathway.

Genetic alterations in goblet cell carcinoids of the vermiform appendix and comparison with gastrointestinal carcinoid tumors

Goblet cell carcinoid is a relatively rare neuroendocrine tumor of the vermiform appendix with poorly understood molecular pathogenesis. We studied the clinicopathologic features and genetic alterations, including allelic loss of chromosomes 11q, 16q, and 18q; sequencing of the K-ras, beta-catenin, and DPC4 (SMAD4) genes; and p53 overexpression and loss of DPC4 by immunohistochemistry; in 16 goblet cell carcinoids. We compared the allelic loss in goblet cell carcinoids to those in 18 gastrointestinal carcinoid tumors. For goblet cell carcinoids, appendiceal perforation was the most common (70%, 7/10) clinical presentation. The mean tumor size was 2.0 +/- 1.5 cm (range, 0.4 to 4.5 cm). The tumor invaded to appendiceal serosa in 50% (8/16) of patients, and two patients had metastasis in lymph nodes or adjoining viscera. With mean follow-up of 24 +/- 14 months (median, 23 mo), 1 of 10 patients had died of disease, and 2 others had tumor recurrence. All four patients with metastases, recurrences, and/or death from disease had serosal involvement at presentation (P =.02). Loss of heterozygosity of chromosome 11q was present in 25% of goblet cell carcinoids, 14% of ileal carcinoid tumors, and 9% of nonileal carcinoid tumors; of chromosome 16q in 38%, 29%, and 0 (P =.02); and of chromosome 18q in 56%, 86%, and 9% (P =.002), respectively. No mutations of K-ras, beta-catenin, or DPC4 genes; p53 overexpression; or loss of staining for DPC4 was present in any tumors. These findings suggest that allelic loss of chromosomes 11q, 16q, and 18q in goblet cell carcinoids and ileal carcinoids may have an important role in the pathogenesis of these tumors.

Primary appendiceal melanoma: fiction or reality?

Melanomas of the gastrointestinal (GI) tract are very rare, and their primary or secondary nature is often difficult to establish. We report the case of a 55-year-old Caucasian female who presented with an appendiceal melanoma. To our knowledge, appendiceal localization of melanoma has never been reported. We review the literature and discuss the issues relating to the origin of gastrointestinal melanomas. In conclusion, even if a primary site of melanoma was not evident in this case, the metastatic nature of this appendiceal melanoma cannot be completely ruled out.

Gastrin releasing peptide and gastrin releasing peptide receptor expression in gastrointestinal carcinoid tumours

AIMS

To establish whether gastrin releasing peptide (GRP) and the GRP receptor (GRPR) are expressed together in gastrointestinal carcinoid tumours.

METHODS

Twenty six carcinoid tumours from the stomach, small intestine, appendix, and colorectum were investigated by immunohistochemistry for GRP and GRPR.

RESULTS

GRP was detected in nine of 19 tumours and GRPR in 22 of 26. Coexpression of both the ligand and receptor was seen in six of 19 cases. GRPR but not GRP was more strongly expressed in appendix and colonic tumours.

CONCLUSIONS

GRP and GRPR are produced by a large number of gastrointestinal carcinoid tumours. An autocrine/paracrine pathway may exist for GRP stimulated cell proliferation in some of these neoplasms, analogous to that seen in small cell anaplastic carcinoma of the lung.

Catestatin--a novel neuropeptide in carcinoid tumors of the appendix

BACKGROUND

The aim of the study was to investigate the immunohistochemical distribution of the novel neuropeptide catestatin in carcinoid tumors. Catestatin, a novel 21 amino acid neuropeptide derived from chromogranin A, was determined immunohistochemically in 30 carcinoid tumors of the appendix and various carcinoid tumors of other localities.

MATERIALS AND METHODS

Paraffin-embedded tissues from 30 carcinoid tumors of the appendix and 16 other carcinoid tumors (5 bronchus-, 5 stomach-, 2 small bowel-, 4 large bowel carcinoid tumors) were incubated with antibodies specific for catestatin, chromogranin A and chromogranin B. Immunohistochemical staining of catestatin was compared to staining with chromogranin A and B. Western blot analysis was performed in one patient with ileal carcinoid.

RESULTS

Thirty patients (20 women, 10 men) with carcinoid tumors of the appendix and 16 patients with other localized carcinoid tumors were investigated. Twenty-six of the appendiceal tumors were localized in the apex of the appendix and 4 tumors in the midportion; none of the tumors was localized at the base of the appendix. Median tumor diameter was 10.7 mm (range 4-18 mm). Immunoreactivity to catesatatin was positive in 28 patients (negative in 2, 0-10% in 11 patients, 11-50% in 14 patients, 51-100% in 3 patients). In 16 patients with carcinoid tumors in various other localizations, catestatin was also expressed. Western blot analysis of ileal carcinoid showed abundant catestatin reactivity with accelerated processing of chromogranin A in the tumor tissue.

CONCLUSION

Catestatin derived from chromogranin A, which is the most widely distributed marker of neuroendocrine tumors, is expressed in high frequency in carcinoid tumors of the appendix (93.3%).

Cytokeratins 7 and 20, Dpc4, and MUC5AC in the distinction of metastatic mucinous carcinomas in the ovary from primary ovarian mucinous tumors: Dpc4 assists in identifying metastatic pancreatic carcinomas

The distinction of metastatic mucinous carcinomas in the ovary from primary ovarian mucinous tumors (atypical proliferative/borderline and carcinoma) can be difficult because of similarities in morphology. We evaluated the immunohistochemical expression of cytokeratins 7 and 20 (CK 7, CK 20), Dpc4 (nuclear transcription factor inactivated in 55% of pancreatic carcinomas), and MUC5AC (a gastric mucin gene) in 57 primary ovarian mucinous tumors (41 atypical proliferative tumors and 16 carcinomas) and 46 metastatic mucinous carcinomas in the ovary. Primary ovarian mucinous tumors were virtually always diffusely positive for CK 7 (98%), Dpc4 (100%), and MUC5AC (98%) and often focally to diffusely positive for CK 20 (68%). Colorectal mucinous carcinomas were diffusely positive for CK 20 (100%) and Dpc4 (89%) and were distinguished from primary ovarian mucinous tumors by their frequent lack of expression of CK 7 and MUC5AC (67% were negative for each marker). Appendiceal carcinomas were diffusely positive for CK 20 (100%) and often negative for CK 7 (71%) but were often positive for MUC5AC (86%) and Dpc4 (100%). When primary ovarian and metastatic colorectal or appendiceal carcinomas shared expression of both CK 7 and CK 20, they could usually be distinguished by the pattern of positivity (diffuse CK 7 and patchy CK 20 in ovarian tumors and patchy CK 7 and diffuse CK 20 in colorectal and appendiceal tumors). Pancreatic carcinomas shared the same pattern of diffuse positivity for CK 7 (100%) and MUC5AC (92%) and focal to diffuse positivity for CK 20 (71%) as primary ovarian mucinous tumors but were negative for Dpc4 in 46%. Loss of Dpc4 expression is useful for distinguishing metastatic pancreatic carcinomas in the ovary from both primary ovarian mucinous tumors and metastatic mucinous carcinomas derived from other sites.

MUC2 is a molecular marker for pseudomyxoma peritonei

Pseudomyxoma peritonei, a syndrome first described by Rokitansky in 1842, is an enigmatic, often fatal intra-abdominal disease characterized by dissecting gelatinous ascites and multifocal peritoneal epithelial implants secreting copious globules of extracellular mucin. Although much past interest in the syndrome has focused on the question of whether the disease arises from primary appendiceal or ovarian mucinous tumors of varying malignant potential, the accumulation of extracellular mucin with its resulting obstruction of abdominal viscera and adhesion formation is one major cause of this disease's morbidity and mortality irrespective of the origin or transformed status of the epithelium secreting it. Because of this and because of the recent discovery and cloning of a series of specific mucin genes responsible for mucin secretion and extracellular deposition, we decided to analyze cases of pseudomyxoma peritonei with specific mucin cDNAs and corresponding antibodies to identify a characteristic marker for this disease which ultimately might be targeted therapeutically. Our study specifically investigated MUC2 and MUC5AC because these two mucins possessed the physicochemical property of being gel-forming, a property exhibited by pseudomyxoma peritonei grossly. Expression of MUC2 and MUC5AC in pseudomyxoma peritonei and in accompanying and non-accompanying appendiceal and ovarian mucinous neoplasms were analyzed by in situ hybridization, immunocytochemistry and digital image analysis. A striking overexpression of both MUC2 and MUC5AC was observed in nearly all cases of pseudomyxoma peritonei of unknown and appendiceal origin. In these cases, however, MUC2 gene expression was more prominent. The mucin:cell ratio averaged 10 to 1 in these cases. The primary ovarian mucinous tumors, some of which exhibited pseudomyxoma ovarii and/or peritoneal implants but not classic pseudomyxoma peritonei, in contrast, expressed only MUC5AC and gave rise to implants where the mucin:cell ratio averaged only 1 to 1. MUC2 overexpression then supported an intestinal rather than ovarian origin for true pseudomyxoma peritonei, irrespective of whether an appendiceal primary was documented. In all cases studied, the fidelity of MUC2 and MUC5AC expression held irrespective of the degree of malignant transformation which was present. MUC2 is therefore a reliable molecular marker for pseudomyxoma peritonei.

Epithelial neoplasms of the appendix and colorectum: an analysis of cell proliferation, apoptosis, and expression of p53, CD44, bcl-2

CONTEXT

Carcinomas of the appendix are usually well-differentiated mucinous adenocarcinomas that tend to produce pseudomyxoma peritonei and do not show metastatic spread until late in the disease process. In contrast, adenocarcinomas of the colon and rectum rarely result in pseudomyxoma peritonei and frequently metastasize, even if mucinous and well differentiated. These differences in behavior may be reflected by differences at the molecular level.

OBJECTIVES

To examine adenocarcinomas and their precursor lesions (adenomas) of the appendix and colorectum and to determine whether differences exist in the numbers of proliferating and apoptotic cells or in expression of p53, bcl-2, and the standard form of CD44 (CD44s).

DESIGN

Retrospective analysis of surgical specimens.

SETTING

Multicenter study.

PATIENTS

Individuals treated surgically for tumors of the appendix or colorectum.

INTERVENTIONS

Sections were cut from formalin-fixed surgical specimens and immunohistochemical tests were performed for Ki-67 (as a marker of proliferating cells), M30 (as a marker of apoptotic cells), p53, CD44s, and bcl-2.

MAIN OUTCOME MEASURES

Expression of Ki-67, M30, p53, CD44s, and bcl-2 in tumor cells.

RESULTS

The appendiceal adenomas showed significantly lower Ki-67 counts, p53 expression, and bcl-2 expression. When compared with adenocarcinomas of the colorectum in general (mucinous and nonmucinous), the appendiceal adenocarcinomas showed significantly lower Ki-67 counts, M30 counts, and CD44s expression. However, when the analysis was confined to well-differentiated mucinous adenocarcinomas, only the M30 count was significantly different.

CONCLUSIONS

The lower proliferative and apoptotic activity of appendiceal carcinomas and the lower CD44s expression are in keeping with their more indolent behavior compared with adenocarcinomas of the colorectum. However, when only the subset of well-differentiated mucinous adenocarcinomas was compared, only the apoptotic activity was different, suggesting that the other differences were related to the morphologic structure of the lesions.

Mucinous and nonmucinous appendiceal adenocarcinomas: different clinicopathological features but similar genetic alterations

The genetic alterations of appendiceal carcinomas have not been reported in detail. We studied the clinicopathological factors and genetic alterations including microsatellite instability, p53 overexpression, and mutations of the K-ras proto-oncogene of 30 appendiceal adenocarcinomas, consisting of 23 mucinous and 7 nonmucinous carcinomas. Sixteen (70%) mucinous carcinomas presented with pseudomyxoma peritonei, but 6 of 7 (86%) nonmucinous carcinomas presented with appendicitis (P =.002). All carcinomas were microsatellite stable, and p53 overexpression was present in only 1 of 30 (3%) carcinomas. K-ras mutation was present in 11 of 20 (55%) carcinomas, including 8 of 16 (50%) mucinous and 3 of 4 (75%) nonmucinous carcinomas. The mean survival of patients with mucinous carcinomas was 26 +/- 19 months compared with 13 +/- 9 months for patients with nonmucinous carcinomas (P =.0002). Our findings suggest that mucinous and nonmucinous carcinomas of appendix have similar genetic alterations, but different clinical presentation and prognosis.

Expression of E-cadherin, b-catenin, and Ki-67 in goblet cell carcinoids of the appendix: an immunohistochemical study with clinical correlation

Goblet cell carcinoid (GCC) of the appendix is a rare entity, of which both the histogenesis and biologic behavior remain controversial, and prognostic tools and therapeutic strategies for this unusual tumor have yet to be defined. The aim of this study was to analyze expression of E-cadherin and b-catenin in GCCs of the appendix with long-term follow-up data as related to the expression of Ki-67 proliferation marker to provide a rationale for treatment guidelines. We analyzed the expression of E-cadherin, b-catenin, and Ki-67 in 11 GCCs of the appendix and control groups of typical carcinoids of the large intestine (n = 29), well to moderately differentiated adenocarcinomas of the colon (n = 10), poorly differentiated adenocarcinomas of the colon (n = 12), and normal appendiceal tissues (n = 10). There was no significant difference between the GCCs and normal appendiceal tissues regarding the expression of E-cadherin or b-catenin (p = 0.297 and 0.103, respectively). The percentage of positive GCC cells ranged between 0.52 and 10.35% (4.27 +/- 0.80), and only one case had a score >10%. Metastatic tumor spread and death were found in high MIB-1 labeling index (LI) cases of GCC (>3%). Our findings suggest that the behavior of the majority of GCCs might be indolent and different from adenocarcinomas because of the preserved expression of E-cadherin and b-catenin and relatively low MIB-1 LI. However, some of these tumors act aggressively and MIB-1 LI might be a good parameter to determine the therapeutic procedure.

Fibromatosis of the mesoappendix

Mesenchymal tumors of the appendix are very rare. Mesenteric fibromatosis is the most common diagnosis in the case of isolated proliferative fibroblastic lesion found in this region. However, the differential diagnosis between fibromatosis and well-differentiated fibrosarcoma (Grade I) can be difficult in some borderline cases. A rare case of proliferative fibroblastic lesion involving the appendix and mesoappendix is presented, and its origin, diagnosis and differential diagnosis are discussed.

Morphological-histochemical study of intestinal carcinoids and K-ras mutation analysis in appendiceal carcinoids

Intestinal carcinoids are potentially malignant neoplasms. Their histogenesis and pathogenesis are currently uncertain. The morphological and histochemical characteristics of twenty intestinal carcinoids are studied. The primary sites of three mucin-producing tumors were examined by electron microscope. Furthermore 11 appendiceal carcinoids were analysed by the polymerase chain reaction (PCR) for the detection of ras and p53 point mutations. Microscopically all carcinoids were of mixed type. Focal mucin production was evident in three carcinoids that metastasised to regional lymph nodes. HID-Alcian blue staining proved that mucin in both primary and secondary foci did not belong to the sulphated group. The secretory granules and mucin droplets found in a single neoplastic cell suggest that carcinoids of the small intestine and some of the appendix arise from the endoderm. Neither ras nor p53 mutations were detected. It seems that ras oncogenes are probably not involved in the pathogenesis of appendiceal carcinoids.

Incidental appendix carcinoid. Value of somatostatin receptor imaging

PURPOSE

Somatostatin receptor scintigraphy is used to diagnose carcinoid of the gastrointestinal tract. Its sensitivity ranges from approximately 75%-100%. Therefore, it was hypothesized that it can be used in the postsurgical follow-up to detect residual carcinoid, recurrence, and metastatic disease.

RESULTS

This article is concerned with the findings of somatostatin receptor imaging performed on a 12-year-old girl 8 weeks after appendectomy. Histologic examination showed an incidental appendix carcinoid. Somatostatin receptor scintigraphy performed for detection of lymph node metastatic spread of the carcinoid showed focal tracer accumulation at the former operative site; subsequently, a right hemicolectomy was performed. However, histologic examination of the surgical tissue showed no evidence for carcinoid.

CONCLUSION

It is concluded that there are some potential pitfalls for somatostatin receptor imaging at least soon after surgery. Therefore, it should not be used to aid in reoperation.

Epithelial noncarcinoid tumors and tumor-like lesions of the appendix. A clinicopathologic study of 184 patients with a multivariate analysis of prognostic factors

BACKGROUND

The current understanding of appendiceal epithelial tumors is based on series composed of relatively small numbers of patients and on case reports. The aim of this study was to perform clinicopathologic correlation, particularly concerning prognosis, on a relatively large series of patients with epithelial tumors and tumor-like lesions of the human vermiform appendix.

METHODS

One hundred eighty-four cases of simple mucoceles, hyperplastic polyps, adenomas, carcinomas, and mucinous tumors of uncertain malignant potential (UMP) were reviewed. Retrospective follow-up data were obtained in carcinoma and UMP tumor cases.

RESULTS

Most neoplasms were of the mucinous type characteristic of the appendix, but a small fraction were nonmucinous and resembled neoplasms typical of the spectrum encountered in the colorectum. Both benign and malignant conditions in some cases showed acellular mucin dissecting the appendiceal wall and mucin outside the appendix. Immunostains were sometimes helpful in identifying epithelial cells within mucus, but hematoxylin and eosin and mucin stains were adequate in most cases. Two factors were significantly associated with survival by multivariate analysis: the presence of mucin outside the right lower quadrant of the abdomen and the presence of epithelial cells in the peritoneal cavity outside the appendix.

CONCLUSIONS

The distribution of mucin within the abdomen and the presence of cells outside the visceral peritoneum of the appendix are important prognostic factors that should be recorded in these neoplasms. Tumors designated as UMP lesions behave in a benign or low grade fashion.

Carcinoid tumour complicating inflammatory bowel disease. A study of two cases with review of the literature

Two cases of carcinoid tumour complicating inflammatory bowel disease (IBD) are presented. Both tumours were located in the appendiceal tip. The first case occurred in a man with Crohn's disease (CD), and the second one in a woman suffering from ulcerative colitis (UC). Histochemical and immunohistochemical studies were not allowed on case 1 because the tumour was not still present on serial sections of the appendix. On case 2, tumour cells were not reactive with Grimelius and Masson-Fontana stainings, but were strongly stained with anti-keratin and anti-chromogranin monoclonal antibodies (MAb), and faintly expressed neuron specific enolase (NSE), and Leu-7. Both cases occurred in inflammatory or damaged mucosa which exhibited Paneth cell metaplasia and hyperplasia and areas indefinite for dysplasia. Along with these lesions, hyperplasia of enteroendocrine cells was pointed out in the neighbouring appendiceal and colonic mucosa by means of anti-chromogranin MAb. These data suggest that the association of carcinoid tumour with IBD, albeit rare, is not coincidental and is the result of hyperplastic and dysplastic troubles that may involve enteroendocrine cells as well as such other derivatives of digestive stem cells as columnar cells, goblet cells and Paneth cells.

Morphological analysis of yolk sac tumor

Morphological analysis of imprint histology and cytology was performed in 7 patients with yolk sac tumor (YST). As a result, histological figures of YST were classified into 4 patterns. Endodermal sinus pattern was most frequently identified, followed by polyvesicular vitelline pattern. Imprint cytology findings of YST were also classified into 4 patterns. Cuboidal cells were most frequently observed; cells and nuclei were both cuboidal in shape and 25-40 mu and 20-25 mu in diameters, respectively. The chromatic showed fine to coarse granular patterns. The nuclear cytoplasmic (N/C) ratio was 50-70%, and each nucleus contained one to four nucleoli. Next to cuboidal cells, spindle-shaped cells were frequently noticed; 20-40 mu in size with spindle-shaped nuclei 10-20 mu in diameter and fine to coarse granular chromatic pattern. Naked cells and bizarre cells were also noticed. It was postulated that cuboidal cells and spindle-shaped cells were originated from the endodermal sinus pattern and the loose reticular pattern of YST, respectively. When utilized with rapid-frozen specimens, imprint cytology of YST is sufficient for rapid diagnosis during operations.

Appendiceal goblet cell carcinoids: a clinicopathological and immunohistochemical study

Goblet cell carcinoids are uncommon but distinctive tumours of the appendix. We have reviewed 11 cases diagnosed within the period 1976-1990. The mean age at presentation was 58 years (range 24-76), with a female:male ratio of 8:3. At presentation, in seven patients tumour was confined to the appendix or mesoappendix (mean age 51) and in four there was extension beyond the appendix (mean age 69). Of the seven patients with localized tumour, six are alive and without clinical disease after a mean follow-up period of 32 months and one died with recurrent tumour after 10 years. Of the four with more extensive disease, two died during follow-up (at 23 months with probable liver metastases and at 16 months with intestinal obstruction) and two are alive, one with disease and one clinically disease-free. Immunohistochemistry showed that all of the tumours stained positively for either neuron-specific enolase, chromogranin A or protein gene product 9.5. No tumour stained with antiserum to substance P and none showed glucagon-like immunoreactivity, but four cases stained positively for pancreatic polypeptide, an unusual feature in midgut carcinoids.

Immunohistochemical and ultrastructural studies of twelve argentaffin and six argyrophil carcinoids of the appendix vermiformis

Endocrine cell types in 12 argentaffin and six argyrophil carcinoids and in nonneoplastic epithelia of the appendix vermiformis were investigated histochemically, immunohistochemically, and ultrastructurally. The nonneoplastic epithelia contained serotonin (Ser), peptide YY (PYY), glicentin (Gli), neurotensin (Neu), and somatostatin (So) cells in decreasing frequency. Out of 30 nonneoplastic Ser cells examined ultrastructurally, 28 cells were EC1 cells and two were non-EC cells. Eleven of 12 argentaffin carcinoids could be immunostained with anti-Ser serum and all of those 11 were composed almost totally of Ser cells. One of the 11 contained a small number of Neu cells. Ultrastructurally, 11 argentaffin carcinoids were composed predominantly of EC1 and/or ECn cells, and one was composed primarily of non-EC cells. Out of the six argyrophil carcinoids, five were argyrophil, non-argentaffin carcinoids; three consisted almost totally of PYY cells; one consisted of 60% PYY cells, 40% So cells and a few Gli cells; and one consisted of Ser cells alone. Ultrastructurally, the first four of those tumors were composed of D1 and/or L cells and the latter tumor was composed of ECn cells. The remaining one argyrophil carcinoid contained a few Ser-positive argentaffin cells and consisted almost totally of ECn cells which were found in both parts, with and without argentaffinity. It is concluded that the appendiceal carcinoids comprise two distinct groups on the basis of the main constituting cell type: Ser-positive, argentaffin carcinoids, composed of EC cells and peptide (especially of PYY)-positive, and Ser-negative, argyrophil non-argentaffin carcinoids of D1 and/or L cells.

Goblet cell carcinoids and related tumors of the vermiform appendix

Appendiceal carcinoids with glandular differentiation pose difficulties in classification and prediction of clinical behavior. Sixty-four such cases were divided into three histologic groups on the basis of routine and immunohistochemical stains: (1) Tubular carcinoids were small and confined to the appendix, had small amounts of intraluminal mucin with few or no goblet cells, were nonargentaffin, lacked serotonin, and were diffusely positive for glucagon. All ten with follow-up (mean, 17 months) were without metastasis. (2) Goblet cell carcinoids were confined to the appendix and mesoappendix, circumferentially surrounded the appendiceal lumen, and were often not suspected grossly. Histologically, they were often mixed with small crypt-like glands and were serotonin positive. All 22 with follow-up (mean, 19 months) were without metastasis whether or not right hemicolectomy was performed. (3) Mixed carcinoid-adenocarcinomas showed spread into the cecum or adjacent viscera at the time of diagnosis and had a large carcinomatous pattern with areas of mucinous, signet-ring, or single-file structure, in addition to goblet cell or insular carcinoid. All patients had right hemicolectomies, and all but two with follow-up died of the disease (mean, 16 months). Although a histologic spectrum exists among carcinoid tumors and certain adenocarcinomas of the appendix, it is possible to delineate three biologically distinct groups. Surgical margins should be taken of all appendices because these tumors often do not form discrete masses.

Granular cell tumour of the appendix in a patient irradiated for a rectal carcinoma

We report on a 47-year-old man with a granular cell tumour of the appendix, discovered incidentally during surgery for a rectal adenocarcinoma that had been irradiated preoperatively. A detailed immunocytochemical analysis revealed positivity for S-100 and neuron-specific enolase (NSE). Electron microscopically, the cytoplasm of the tumour cells contained numerous pleomorphic lysosomes. In the appendix tissue adjacent to the tumour a neuroma and the histological features of radiation injury were present. Our findings suggest that this granular cell tumour may have originated from a pre-existing appendix neuroma which underwent granular degeneration, possibly as a result of radiation.

Appendiceal carcinoids: correlation of histology and immunohistochemistry

In order to compare histologic subtypes and endocrine profiles, immunohistochemical and silver stains were performed on 120 appendiceal carcinoids. Forty-three were predominantly insular; 21 were mixed insular, glandular, and trabecular; 33 were goblet cell; 17 were tubular; and five were clear cell carcinoids. Insular, mixed, and clear cell carcinoids were generally diffusely argentaffin and positive for chromogranin, neuron-specific enolase (NSE), and serotonin. Occasional tumors of insular or mixed patterns had scattered cells that stained weakly for glucagon, calcitonin, adrenocorticotrophic hormone (ACTH), somatostatin, cholecystokinin (CCK), human pancreatic polypeptide (HPP), or gastrin. Most had S-100-positive sustentacular cells. Less than half were positive for carcinoembryonic antigen (CEA). Many were cytokeratin-positive, but often focally. Goblet cell carcinoids contained few endocrine cells, but these were strongly argentaffin and positive for serotonin in nearly all, and positive for HPP in almost a third. Tubular carcinoids lacked argentaffinity and serotonin but were diffusely and strongly positive for glucagon. All goblet cell and tubular carcinoids were diffusely positive for CEA and cytokeratin. Somatostatin stained strongly in a single tumor, which had psammoma bodies and was in a patient with neurofibromatosis. In all groups, argentaffinity correlated with serotonin positivity, and argyrophilia with chromogranin positivity, although the latter was somewhat more sensitive. We conclude that among appendiceal carcinoids, the endocrine content varies according to histologic subtype.

Lectin expression in carcinoid tumours of the gastrointestinal tract

The binding of peroxidase-conjugated Dolichos biflorus (DBA), Triticum vulgaris (WGA), Canavalia ensiformis (Con A), Arachis hypogaea (PNA), Lotus tetragonolobus, and Bandeiraea simplicifolia I (BSAI) to gastrointestinal carcinoid tumours was studied. The results indicate that carcinoid tumour cells express certain carbohydrates similar to those present in the adjacent surface epithelium. The differences in the lectin-binding properties of carcinoid tumours of different sites of the gastrointestinal tract are closely related to the regional differences in the lectin binding of adjacent surface epithelium. These observations therefore form a useful basis for further studies in the application of lectin histochemistry to elucidate the histogenesis of carcinoid tumours.

Subepithelial neuroendocrine cells and carcinoid tumours of the human small intestine and appendix. A comparative immunohistochemical study with regard to serotonin, neuron-specific enolase and S-100 protein reactivity

A comparative immunocytochemical study was performed of subepithelial neuroendocrine cells of the human small intestine and appendix and carcinoid tumours of these sites, using a monoclonal antibody to serotonin and polyclonal antisera against neuron-specific enolase (NSE) and S-100 protein. Subepithelial neuroendocrine cells were easily identified in the lamina propria of the appendix. These cells, which sometimes occurred in aggregates, displayed serotonin and NSE immunoreactivity and were surrounded by S-100 protein immunoreactive cells, presumably of Schwann cell origin. In the appendix scattered cells with corresponding morphological features and immunoreactivity were also observed deep in the submucosa. In addition, subepithelial neuroendocrine cells were sparsely present in the lamina propria of the small intestine, occurring only as single cells in the deeper part of the mucosa below or between the epithelial crypts. Most appendiceal carcinoid tumours (11 of 12 examined cases) were biphasic and consisted of neuroendocrine tumour cells with intermingled S-100 protein immunoreactive cells (Schwann cells) with long cytoplasmic extensions. However, small intestinal (11 cases) and caecal (10 cases) carcinoids lacked S-100 protein immunoreactive cells as an integral component. The results indicate that the appendiceal carcinoids are mostly closely related structurally to the subepithelial neuroendocrine and Schwann cell aggregates of the lamina propria and are thus presumed to be histogenetically related to this cell system, while the histogenesis of small-intestinal and caecal carcinoids remains less clear.

Composite carcinoma-carcinoid tumors of the gastrointestinal tract. A morphologic, histochemical, and immunocytochemical study

A morphologic, histochemical, and immunocytochemical study of 20 cases of pure gastrointestinal carcinoids, adenocarcinomas, and mixed neoplasms composed of both elements, so-called composite carcinoma-carcinoid tumors (CCC), was undertaken in order to correlate the morphologic patterns with the immunocytochemical localization of carcinoembryonic antigen (CEA), serotonin, and a battery of polypeptide hormones (calcitonin, glucagon, insulin, gastrin, somatostatin, and adrenocorticotropin [ACTH]). Paraffin sections from five pure carcinoids, seven pure adenocarcinomas, and eight CCC from the stomach, small bowel, appendix, and colon were studied with mucicarmine, silver impregnation stains, and a peroxidase-anti-peroxidase technic. Of the eight CCC, all were mucin positive, four were argyrophilic, and three were argentaffin positive. CEA was present in all eight, serotonin in seven, and calcitonin in one. No other neurohormonal peptides were demonstrated. The distribution of serotonin and CEA generally corresponded to the morphologic pattern, but discordance was observed in two cases, i.e., serotonin was not always localized to areas of carcinoid and CEA not always confined to areas of carcinoma. All five pure carcinoids demonstrated intracytoplasmic localization of serotonin, whereas none contained intracytoplasmic CEA. In two cases, CEA was present within acinar lumens only. The seven colonic adenocarcinomas were argyrophil and argentaffin negative. All contained CEA within the cytoplasm and in gland lumens. None contained serotonin. None of the neurohormonal peptides was localized in either pure adenocarcinomas or carcinoids. This study reveals that among gastrointestinal neoplasms displaying morphologic patterns of adenocarcinoma and carcinoid, immunocytochemical localization of CEA and serotonin confirms their bidirectional differentiation and justifies the designation "composite carcinoma-carcinoid."