Coexisting well-differentiated and anaplastic thyroid carcinoma in the same primary resection specimen: immunophenotypic and genetic comparison of the two components in a consecutive series of 13 cases and a review of the literature

Anaplastic carcinoma (AC) is a rare but highly aggressive form of thyroid cancer. It mostly arises on a background of pre-existing well-differentiated cancer (WDC); however, whether it evolves directly from a WDC or originates as a second independent neoplasm is still to be defined. To obtain further insights into these mechanisms, we performed morphological, immunohistochemical, and next-generation sequencing analyses to compare AC and its associated WDC in a subset of 13 surgically resected specimens. Histologically, most WDC were of aggressive subtypes. Papillary carcinomas (8 cases; 62%) were tall cell (4/8), columnar (1/8), classic with hobnail features (1/8), classic and follicular variant in the remaining 2 cases; Hürthle cell and follicular carcinomas were present in 5 (38%) and in 1 (8%) patient, respectively. One patient harbored both a PTC, follicular variant, and a Hürthle cell carcinoma. We did not find any correlation between a histotype of WDC and a specific anaplastic growth pattern. Immunohistochemically, ACs retained pankeratin/PAX8 expression but with significantly lower levels than WDCs, and they tended to lose TTF1 expression, as can be expected within a dedifferentiation process. In addition, AC showed a more frequent expression of p63 and/or SMA, a mutated pattern of p53, and an abnormal expression of p16. Genetic analysis showed that the number of mutations was higher in AC than in the associated WDC, confirming a role of the progressive accumulation of genetic damage in this transition. We observed that mutations found in the WDCs were consistently identified in the anaplastic counterparts, further supporting the hypothesis of a developmental link.

Gastrointestinal mixed adenoneuroendocrine carcinoma (MANEC): An immunohistochemistry study of 13 microsatellite stable cases

BACKGROUND

Mixed adenoneuroendocrine carcinoma (MANEC) is currently included in the category of neuroendocrine carcinomas but the therapeutically management is not yet defined.

AIMS

To present the immunohistochemical (IHC) features of the epithelial mesenchymal transition (EMT) of MANEC.

MATERIALS AND METHODS

The clinicopathological features of 13 consecutive cases of MANEC (6 gastric and 7 colorectal) were correlated with the IHC expression of the biomarkers E-cadherin, β-catenin, N-cadherin, vimentin, maspin, CD44 and S100. In all of the cases open surgery was performed.

RESULTS

All of the cases showed microsatellite stable status, expressed E-cadherin and membrane β-catenin in both components (neuroendocrine and adenocarcinoma) and were negative for N-cadherin, vimentin and S-100. The colorectal MANECs were negative for maspin. In gastric MANECs, maspin showed cytoplasm positivity in the neuroendocrine component and nuclear translocation in the adenocarcinoma cells. CD44 was positive in all of the cases, in both components. No tumor buddings were identified. Three of the 13 patients survived for at least 32 months, all of them showing lymphatic emboli but not lymph node metastases. Pure neuroendocrine lymph node metastases were seen in only four of the cases: one from stomach, two of the ascending colon and two cases of the upper rectum.

CONCLUSIONS

Gastrointestinal MANEC is a microsatellite stable tumor with nodular growth, which components might originate from a CD44-positive stem-like precursor cell. Lymph node status remains the most reliable prognostic parameter and agressivity seems to not be influenced by tumor budding degree or EMT-related features. The histologic aspect of metastatic component (neuroendocrine versus adenocarcinoma) should be included in the histopathological reports and might be used for establishing the proper-targeted therapy of MANEC.

Genomic and Transcriptomic Profiling of Combined Hepatocellular and Intrahepatic Cholangiocarcinoma Reveals Distinct Molecular Subtypes

We performed genomic and transcriptomic sequencing of 133 combined hepatocellular and intrahepatic cholangiocarcinoma (cHCC-ICC) cases, including separate, combined, and mixed subtypes. Integrative comparison of cHCC-ICC with hepatocellular carcinoma and intrahepatic cholangiocarcinoma revealed that combined and mixed type cHCC-ICCs are distinct subtypes with different clinical and molecular features. Integrating laser microdissection, cancer cell fraction analysis, and single nucleus sequencing, we revealed both mono- and multiclonal origins in the separate type cHCC-ICCs, whereas combined and mixed type cHCC-ICCs were all monoclonal origin. Notably, cHCC-ICCs showed significantly higher expression of Nestin, suggesting Nestin may serve as a biomarker for diagnosing cHCC-ICC. Our results provide important biological and clinical insights into cHCC-ICC.

Cytologic and Histologic Features of Pleomorphic Undifferentiated Sarcoma Arising in a Hybrid Hemosiderotic Fibrolipomatous Tumor and Pleomorphic Hyalinizing Angiectatic Tumor: Report of an Unusual Case with a Literature Review

BACKGROUND

Pleomorphic hyalinizing angiectatic tumor (PHAT) and hemosiderotic fibrolipomatous tumor (HFLT) are low-grade neoplasms that share clinicopathologic features and recurring translocation t(1;10)(p22;q24) involving the TGFBR3 and MGEA5 genes. Coexistence of these tumors with a high-grade sarcoma is exceedingly rare and the cytologic features have not been widely described in the literature.

CASE

A 55-year-old female presented with a soft tissue tumor on the dorsum of the foot. Cytologic smears and corresponding core biopsies were composed of a population of markedly pleomorphic spindle cells seen singly and in loose clusters within a myxofibrous matrix and infiltrating fat, with coarse chromatin, prominent nucleoli, irregular nuclear contours and delicate to vacuolated cytoplasm. Intracytoplasmic hemosiderin granules and rare intranuclear cytoplasmic pseudoinclusions were identified. The histologic features of the excisional biopsy mirrored those of the cytologic preparations, but also demonstrated cellular foci of higher-grade sarcoma composed of markedly pleomorphic tumor cells with large vesicular nuclei and prominent nucleoli, exhibiting a mitotic index of 12 mitotic figures per 10 high-powered fields.

CONCLUSION

While HFLT/PHAT generally can be managed by wide local excision, it is important to be aware of their capacity to harbor higher-grade lesions with metastatic potential which may require more radical surgical excision.

Mixed epithelial and stromal tumor of the kidney: report of a rare case and review of literature

Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare benign tumor composed of epithelial and stromal cells. We report a rare male case with detailed clinicopathological data and follow-up information. The patient presented with gross hematuria. Computed tomography (CT) and magnetic resonance imaging study showed a 60 mm×40 mm cystic lesion with thickened septa and minimal contrast enhancement at the lower pole of the right kidney. The patient underwent nephron sparing surgery (NSS). Intraoperative frozen section showed benign histological features without significant cytologic atypia and mitosis. By additional immunohistochemistry investigations, the epithelial component was positive for cytokeratin-7, high molecular weight cytokeratin, and PAX-8. The stromal component showed strong positivity for vimentin and smooth-muscle actin. This case emphasizes that it is difficult to establish a precise diagnosis of MESTK preoperatively due to lack of any typical radiological features. Thus, intraoperative frozen section is of great clinical significance for NSS with preservation of kidney function. Additionally, regular follow-up is necessary for the MESTK with malignant potential.

A rare case of malignant pediatric ectomesenchymoma arising from the cerebrum

Malignant ectomesenchymoma is a rare tumor that contains both ectodermal and mesenchymal elements. So far, only 7 patients with a manifestation in the cerebrum (with confirmed clinicopathological data) have been reported. A 4-year-old girl was present at our hospital with a 3-week history of intermittent sudden dizzy with no apparent cause. MRI showed an irregular enhanced lesion in the left frontal-parietal lobe and lateral ventricle with peripheral gadolinium-enhancement with a significant surrounding edema. Total removal of the tumor was performed. Histological examination of the resected tumor revealed a mixed astrocytoma and anaplastic ependymoma component with undifferentiated mesenchymal spindle cell component. Generally speaking, the main malignant part in most cases of malignant ectomesenchymoma (MEM) is the mesenchymal component. In the present case, the malignant component was both in the mesenchymal and ectodermal part. In particular, the mesenchymal part was mainly composed of spindle cells, and the ectodermal part primarily consisted of gliomatous component and anaplastic ependymoma component. The patient was then treated with chemotherapy and as regard to the prognosis, there was no evidence of tumor recurrence at the 5 months' follow-up. The long term follow-up is still in progress.

Endoscopic mucosal resection of duodenal bulb adenocarcinoma with neuroendocrine features: An extremely rare case report

Duodenal adenocarcinoma, especially duodenal bulb with neuroendocrine features (NEF), is extremely rare. Here, we report one such case of duodenal bulb adenocarcinoma with neuroendocrine features. A 63-year-old Han Chinese woman was admitted to our department with the diagnosis of a duodenal bulb polyp and underwent an endoscopic mucosal resection. The pathological findings confirmed it as duodenal bulb adenocarcinoma with NEF. The patient remains curative after one and half a years of follow-up. Duodenal adenocarcinoma with NEF might be a low malignant neuroendocrine tumor rather than a conventional adenocarcinoma. Endoscopic treatment, including endoscopic mucosal resection, might be an ideal option for the adenocarcinomas with NEF.

Coexisting epithelioid trophoblastic tumor and placental site trophoblastic tumor of the uterus following a term pregnancy: report of a case and review of literature

Gestational trophoblastic neoplasms are a group of fetal trophoblastic tumors including choriocarcinomas, epithelioid trophoblastic tumors (ETTs), and placental site trophoblastic tumors (PSTTs). Mixed gestational trophoblastic neoplasms are extremely rare. The existence of mixed gestational trophoblastic neoplasms that were composed of choriocarcinoma and/or PSTT and/or ETT was also reported. Herein, we present a case of uterine mixed gestational trophoblastic neoplasm which is ETT admixed with PSTT, and reviewed 9 cases of mixed gestational trophoblastic neoplasms reported in English literature available. The most common combination was a choriocarcinoma admixed with an ETT and/or PSTT. Mixed gestational trophoblastic neoplasms present in women of reproductive age and rare in postmenopausal, Abnormal vaginal bleeding is the most common presenting symptom, serum β-HCG levels are elevated, mostly below 2500 mIU/ml, the tumor was limited to uterus in 7 cases, the rest of 3 with pulmonary metastases at the time of diagnosis. Mixed gestational trophoblastic neoplasms have more similar clinical features with intermediate trophoblastic tumors (ITTs). Total hysterectomy with lymph node dissection is recommended treatment for mixed gestational trophoblastic neoplasms, and chemotherapy should be used in patients with metastatic disease and with nonmetastatic disease who have adverse prognostic factors.

Endometrial stromal sarcoma with endometrioid adenocarcinoma of the uterus: a case report

Endometrial stromal sarcoma (ESS) is a rare malignant neoplasm of the uterus. We report the first case of undifferentiated ESS (UES) coexistent with grade 1 endometrioid adenocarcinoma in a 73-year-old female who presented with irregular vaginal bleeding for 4 days after menopause 20 years. Imaging examination including Magnetic Resonance Imaging (MRI) demonstrated multi-node reflection in uterine cavity without metastatic lesions, and the endometrium essentially normal. Grossly, a grey-red breakable polypoid tumor of 4.5×3.0×2.0 cm was recognized in the posterior uterine wall with surrounding slight rough endometrium. Microscopically, the tumor was composed of a larger component of undifferentiated stromal sarcoma that was distinct from a smaller endometrioid adenocarcinoma. The separate components of the tumor could be supported in immunohistochemical studies. There was no sign of recurrence for postoperative 6 months.

Human epidermal growth factor receptor 2 expression in mixed gastric carcinoma

AIM: To investigate human epidermal growth factor receptor 2 (HER2) amplification and protein expression in mixed gastric carcinoma.

METHODS: Fluorescence in situ hybridization and immunohistochemistry were used to detect HER2 amplification and protein expression in 277 cases of mixed gastric carcinoma. Protein staining intensity was rate as 1+, 2+, or 3+.

RESULTS: Of the 277 cases, 114 (41.2%) expressed HER2 protein. HER2 3+ staining was observed in 28/277 (10.1%) cases, 2+ in 37/277 (13.4%) cases, and 1+ in 49/277 (17.7%) cases. A HER2 amplification rate of 17% was detected, of which 25/28 (89.3%) were observed in the HER2 3+ staining group, 17/37 (45.9%) in 2+, and 5/49 (10.2%) in 1+. Of the 47 patients with HER2 amplification who received chemotherapy plus trastuzumab, 22 demonstrated median progression-free and overall survivals of 9.1 mo and 16.7 mo, respectively, which were significantly better than those achieved with chemotherapy alone (5.6 mo and 12.1 mo, respectively) in 19 previously treated patients (Ps < 0.05).

CONCLUSION: HER2 detection in mixed gastric carcinoma displays high heterogeneity. Relatively quantitative parameters are needed for assessing the level of HER2 amplification and protein expression.

Transition between urothelial carcinoma in situ and non-invasive micropapillary carcinoma as a pivot connection between diverse morphologies of bladder carcinoma: a case report of urothelial carcinoma with villoglandular differentiation

Urothelial carcinoma has numerous histological variants, and these variants may coexist in a single case. Here, we present a case of a 70-year-old man with urothelial carcinoma of the bladder with a maximal diameter of 5 mm that involved micropapillary and plasmacytoid variants, with villoglandular differentiation. The presence of these variants was confirmed by pathological examination of a transurethral resection specimen, and high-grade urothelial carcinoma was found as a minor component. Although this bladder carcinoma was classified as pT1, cystoprostatectomy, urethrectomy, and lymphadenectomy were performed due to the presence of the micropapillary and plasmacytoid variants, which are known to be aggressive. Examination of a surgically resected specimen revealed no carcinoma. A transition between urothelial carcinoma in situ and non-invasive micropapillary carcinoma was found to be a pivot point connecting the diverse morphologies of this bladder carcinoma, from which there existed two pathways. One pathway was from urothelial carcinoma in situ to the plasmacytoid variant through invasive high-grade urothelial carcinoma, and the other was from non-invasive micropapillary carcinoma to urothelial carcinoma with villoglandular differentiation or to the micropapillary variant. This is the 16th reported case of urothelial carcinoma with villoglandular differentiation in the literature. As urothelial carcinoma with villoglandular differentiation is often associated with aggressive variants, as shown in our case, it should be reported whenever encountered in routine pathological practice.

Mixed adenoneuroendocrine carcinoma of the ampulla: Two case reports

Mixed adenoneuroendocrine carcinoma (MANEC) is a malignant tumor with adenocarcinoma and neuroendocrine components, with ≥ 30% of each component required. MANEC of the ampulla is rare. To the best of our knowledge, only 15 cases of MANEC of the ampulla have been reported in the English-language literature. Here, we report two cases of MANEC of the ampulla in two women aged 43 and 60 years, which was confirmed by histology after pancreaticoduodenectomy. These tumors contained neuroendocrine and adenocarcinoma components. The neuroendocrine components were positive for chromogranin A (CgA), synaptophysin (Syn) and CD56 by immunostaining. The adenocarcinoma components were negative for CgA, Syn and CD56. Both cases were T3N0M0 (Stage IIIA). They survived for 15 and 20 mo after surgery, respectively. A brief discussion about the histopathological features, clinical behavior and treatment of MANEC of ampulla, and review of the relevant literature are presented.

Mixed adenoneuroendocrine carcinoma of gastrointestinal tract: report of two cases

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare tumor of the gastrointestinal tract that consists of a dual adenocarcinomatous and neuroendocrine differentiation, each component representing at least 30% of the tumor. To date, only seven cases have been reported in the cecum, and less than 40 in the stomach. Our first case was diagnosed in a 74-years-old female as a polypoid lesion of the cecum with direct invasion in the transverse colon, without lymph node metastases. The second case was diagnosed in the stomach of a 46-years-old male as a polypoid tumor of the antral region that invaded the pancreas and presented metastases in 22 regional lymph nodes. The metastatic tissue was represented by the glandular component. In both cases, the tumor consisted of a moderately-differentiated tubular adenocarcinoma (with mucinous component in Case 1) intermingled with neuroendocrine carcinoma. Ki67 index was lower than 20% in Case 1, respectively higher than 20% in Case 2. The neuroendocrine component was marked by synaptophysin and neuron specific enolase, being negative for Keratins 7/20. The neuroendocrine component represented 60% in Case 1, and 40% in Case 2, respectively. The glandular components were marked by carcinoembryonic antigen, maspin and keratin 20/7 (Case 1/2). Both cases were proved to be microsatellite stable. Independently by the localization and tumor stage, MANECs appear to be highly malignant tumors, with high risk for distant metastases. The aggressiveness seems to depend on the endocrine component, independent of its proportion. The neuroendocrine component could be a dedifferentiated adenocarcinoma with a neuroendocrine phenotype.

Mixed adenoneuroendocrine carcinoma of gastrointestinal tract: Report of two cases

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare tumor of the gastrointestinal tract that consists of a dual adenocarcinomatous and neuroendocrine differentiation, each component representing at least 30% of the tumor. To date, only seven cases have been reported in the cecum, and less than 40 in the stomach. Our first case was diagnosed in a 74-years-old female as a polypoid lesion of the cecum with direct invasion in the transverse colon, without lymph node metastases. The second case was diagnosed in the stomach of a 46-years-old male as a polypoid tumor of the antral region that invaded the pancreas and presented metastases in 22 regional lymph nodes. The metastatic tissue was represented by the glandular component. In both cases, the tumor consisted of a moderately-differentiated tubular adenocarcinoma (with mucinous component in Case 1) intermingled with neuroendocrine carcinoma. Ki67 index was lower than 20% in Case 1, respectively higher than 20% in Case 2. The neuroendocrine component was marked by synaptophysin and neuron specific enolase, being negative for Keratins 7/20. The neuroendocrine component represented 60% in Case 1, and 40% in Case 2, respectively. The glandular components were marked by carcinoembryonic antigen, maspin and keratin 20/7 (Case 1/2). Both cases were proved to be microsatellite stable. Independently by the localization and tumor stage, MANECs appear to be highly malignant tumors, with high risk for distant metastases. The aggressiveness seems to depend on the endocrine component, independent of its proportion. The neuroendocrine component could be a dedifferentiated adenocarcinoma with a neuroendocrine phenotype.

Ovarian malignant mixed germ cell tumor with clear cell carcinoma in a postmenopausal woman

Malignant germ cell tumors of the ovary are very rare and account for about 2-5% of all ovarian tumors of germ origin. Most patients are adolescent and young women, approximately two-thirds of them are under 20 years of age, occasionally in postmenopausal women. But clear cell carcinoma usually occurs in older patients (median age: 57-year old), and closely related with endometriosis. Here we report a case of a 55-year old woman with right ovarian mass that discovered by B ultrasonic. Her serum levels of human chorionic gonadotropin (hCG) and α-fetoprotein (AFP) were elevated. Pathological examination revealed the tumor to be a mixed germ cell tumor (yolk sac tumor, embryonal carcinoma and mature teratoma) with clear cell carcinoma in a background of endometriosis. Immunohistochemical staining showed SALL4 and PLAP were positive in germ cell tumor area, hCG, CD30 and OCT4 were positive in epithelial-like cells and giant synctiotrophoblastic cells, AFP, AAT, CD117 and Glyp3 were positive in yolk sac component, EMA and CK7 were positive in clear cell carcinoma, CD10 was positive in endometrial cells of endometriotic area. She was treated with surgery followed by seven courses of chemotherapy. She is well and serum levels of hCG and AFP have been decreased to normal levels.

Histopathology of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is currently the sixth most common type of cancer with a high mortality rate and an increasing incidence worldwide. Its etiology is usually linked to environmental, dietary or life-style factors. HCC most commonly arises in a cirrhotic liver but interestingly an increasing proportion of HCCs develop in the non-fibrotic or minimal fibrotic liver and a shift in the underlying etiology can be observed. Although this process is yet to be completely understood, this changing scenario also has impact on the material seen by pathologists, presenting them with new diagnostic dilemmas. Histopathologic criteria for diagnosing classical, progressed HCC are well established and known, but with an increase in detection of small and early HCCs due to routine screening programs, the diagnosis of these small lesions in core needle biopsies poses a difficult challenge. These lesions can be far more difficult to distinguish from one another than progressed HCC, which is usually a clear cut hematoxylin and eosin diagnosis. Furthermore lesions thought to derive from progenitor cells have recently been reclassified in the WHO. This review summarizes recent developments and tries to put new HCC biomarkers in context with the WHOs reclassification. Furthermore it also addresses the group of tumors known as combined hepatocellular-cholangiocellular carcinomas.

Pancreatic adenocarcinosarcoma of monoclonal origin: A case report

Adenocarcinosarcoma, a neoplasm containing both carcinomatous and sarcomatous components, is a rare form of a cancer and the pathophysiology is currently poorly understood. Moreover, definitive treatment guidelines for this disease have not yet been established. Pancreatic adenocarcinosarcoma is even more rare and the prognosis is fatal. Here, we report a case of a 77-year-old male with pancreatic adenocarcinosarcoma and metastasis to the liver. The patient presented at our hospital with uncontrolled glucose levels and diabetes mellitus. The patient’s laboratory findings were unremarkable with the exception of elevated carbohydrate antigen 19-9 levels. Biopsies of the tumors in the pancreas and the liver revealed two types of tumors: pancreatic adenocarcinoma and a poorly differentiated sarcoma. To determine if KRAS mutations were present, we performed a peptide nucleic acid (PNA) clamp PCR-based assay. DNA sequencing by PNA clamp PCR identified a point mutation in codon 12 of exon 2 within KRAS from both tumor types. Because the KRAS mutation is observed in both tumor components, our findings support a monoclonal tumor origin followed by subsequent divergent differentiation into the sarcomatous and carcinomatous tumor populations. After we considered the patient’s status and the late stage of tumor detection, gemcitabine chemotherapy was administered.

Solid pseudopapillary neoplasms of the pancreas: clinicopathologic features and surgical treatment of 19 cases

Solid pseudopapillary neoplasms (SPNs) of the pancreas are very rare neoplasms. The present study is to summarize our experience of the diagnosis, surgical treatment and prognosis of SPNs. The clinical data of 19 cases that underwent surgery for pathologically confirmed SPNs, admitted in our hospital from Mar. 2007 to Mar. 2013, were analyzed retrospectively. The clinicopathologic feature, surgical treatment and prognosis were described in detail. The 19 patients were 17 females and 2 males, with a median age of 29 years. All patients had curative resections, including eight distal pancreatectomies with splenectomy, four spleen-preserving distal pancreatectomies, two pancreaticoduodenectomies, two pylorus-preserving pancreaticoduodenectomies, two duodenum-preserving pancreatic head resections and one central pancreatectomy. The tumors were 6.3 cm in diameter on average, and were mostly located in the body or tail of the pancreas (63.2%). Pathologically, the tumors contained a mixture of solid, cystic, and pseudopapillary patterns in various proportions. None of the patients had lymph nodes metastases and local invasion. All patients were alive and disease-free at a median follow-up of 38.4 months. SPNs are rare neoplasms, typically affecting young women without notable symptoms, with a low malignant potential but excellent prognosis. Radical surgical resection with clear margins is the treatment of choice.

Mesothelioma of the tunica vaginalis testis with prominent adenomatoid features: a case report

Malignant mesotheliomas of the testis arise from the tunica vaginalis, formed from the evagination of the abdominal peritoneum into the scrotum. It is an extremely rare tumor representing 0.3% to 5% of all malignant mesotheliomas. We presented an interesting case of 68-year-old male with swelling and slightly painful in the right scrotum. Histologically, the lesion were composed of small tubular, microcystic, gland lined by flattened epithelioid cells and vague signet ring cells set in a myxofibrous stroma, which is resemblance to adenomatoid tumor. But the tumor cells showed significant atypical cytologic morphology and invaded into spermatic cord tissue, which indicated the diagnosis of malignant tumor. Immunohistochemistry study showed positive expression of CK, CK5/6, CK7, Calretinin, D2-40 and Vimentin which indicated the diagnosis of malignant mesothelioma. This case of mesothelioma should be classified as epithelial in type. To our knowledge, the mesothelioma of the tunica vaginalis testis with adenomatoid tumor-like microscopic features is very rare.

Total pancreatectomy for metachronous mixed acinar-ductal carcinoma in a remnant pancreas

In October 2009, a 71-year-old female was diagnosed with a cystic tumor in the tail of the pancreas with an irregular dilatation of the main pancreatic duct in the body and tail of the pancreas. A distal pancreatectomy with splenectomy, and partial resection of the duodenum, jejunum and transverse colon was performed. In March 2011, a follow-up computed tomography scan showed a low density mass at the head of the remnant pancreas. We diagnosed it as a recurrence of the tumor and performed a total pancreatectomy for the remnant pancreas. In the histological evaluation of the resected specimen of the distal pancreas, the neoplastic cells formed an acinar and papillary structure that extended into the main pancreatic duct. Mucin5AC, α1-antitrypsin (α-AT) and carcinoembryonic antigen (CEA) were detected in the tumor cells by immunohistochemistry. In the resected head of the pancreas, the tumor was composed of both acinar and ductal elements with a mottled pattern. The proportions of each element were approximately 40% and 60%, respectively. Strongly positive α-AT cells were detected in the acinar element. Some tumor cells were also CEA positive. However, the staining for synaptophysin and chromogranin A was negative in the tumor cells. Ultimately, we diagnosed the tumor as a recurrence of mixed acinar-ductal carcinoma in the remnant pancreas. In conclusion, we report here a rare case of repeated pancreatic resection for multicentric lesions of mixed acinar-ductal carcinoma of the pancreas.

Neuroendocrine liver metastasis in gastric mixed adenoneuroendocrine carcinoma with trilineage cell differentiation: a case report

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare disease, which mostly occurs in the gastrointestinal tract and pancreas. Here we report a case of gastric MANEC with tri-lineage differentiation in which only the neuroendocrine component had metastasized to the liver. Liver and gastric masses were detected by abdominal computed tomography, and the preoperative relationship between liver and gastric masses was unknown. The histopathological analysis after operation confirmed the gastric mass to be MANEC, whereas the liver mass was actually the metastatic neuroendocrine component of the gastric MANEC. In the pathologic diagnosis, tri-lineage differentiation, including tubular adenocarcinoma, neuroendocrine carcinoma and squamous cell carcinoma was observed in the gastric MANEC tissues. The mitotic and Ki-67 labeling indexes of the resected tumor tissue were high, and thus, the tumor was classified as a grade G3 neuroendocrine carcinoma, which has a poor prognosis. Multiple low-density masses were found in the right lobe of the liver 2.5 months after operation.

Clinicopathological features of an ascending colon mixed adenoneuroendocrine carcinoma with clinical serosal invasion

Mixed adenoneuroendocrine carcinoma (MANEC) is exceedingly rare with a poor outcome. In this article, we reported a MANEC in a 68-year-old woman with a symptom of abdominal pain and distension. MANEC derived from the ascending colon with highly aggressive behavior. The diagnosis and distinguish of MANEC must base on histological findings and immunohistochemical findings. In this case, microscopic observation showed tumor cells were arranged in conglobate and nested by fibrous tissue with a visible cell atypia and mitotic. NEC-like and exocrine glandular cells were also been seen in a single neoplasm. MANEC tissues were immunopositive for CK, CK20, P53, CK7, CDX-2, Ki-67 (70%+), E-cad, CD56, CEA, Syn, villin and CgA, and immunonegative for CA125, NSE, ER and PR. Here, the patient was treated by surgical operation and was followed-up near 3 months, no local recurrence and distant metastasis.

Combined hepatocellular carcinoma - cholangiocarcinoma harboring a metastasis of colon adenocarcinoma

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CC) represents a rare form of primary hepatic neoplasia. We report an unusual case of tumor-to-tumor metastasis: a cHCC-CC harboring a metastasis of colon adenocarcinoma developed in a 59 year old patient with alcohol-related liver cirrhosis. To the best of our knowledge, this is the first case of such a simultaneous occurrence.

Composite hemangioendothelioma arising from the kidney: case report with review of the literature

Reported herein is a medical curiosities vascular tumor primary arising from the kidney and exhibiting unique histopathological features. A 32-year-old woman underwent a total nephrectomy of right kidney because of a mass localized in the inferior pole. Distinct from other vascular lesions, on histology the tumor had a peculiar composite pattern, consisting of benign and malignant vascular components, which were haphazardly intermixed without any definite margins. The malignant component was composed of epithelioid hemangioendothelioma (45%) and angiosarcoma (50%) with moderate differentiation. Immunohistochemically, the oval to cuboidal to spindle tumor cells expressed only endothelial markers (CD31, CD34 and factor VIII-related antigen). And the angiosarcomatous component was characterized by the presence of a greater proliferation index Ki-67. Unlike other epithelial tumors, smooth muscle actin (SMA), cytokeratin, EMA and S-100 were all negative in the epithelioid tumor cells. These findings led to the diagnosis of a low-grade vascular neoplasm with morphological features consistent with so-called composite hemangioendothelioma (CHE). At 11 month follow up the patient was alive, without evidence of tumor recurrence. CHE is an extremely rare vascular neoplasm, with borderline malignant potential, which mostly occurs in distal extremity of the limbs at the cutaneous level and, only 30 cases have been previously described until now. To our knowledge, this is the first report of CHE arising from the kidney and widens the spectrum of primary vascular tumors arising in the kidney.

Intraductal papillary neoplasm of the bile duct accompanying biliary mixed adenoneuroendocrine carcinoma

We present the first case of an intraductal papillary neoplasm of the bile duct (IPNB) accompanying a mixed adenoneuroendocrine carcinoma (MANEC). A 74-year-old woman presented with fever of unknown cause. Laboratory data revealed jaundice and liver injury. Contrast-enhanced computed tomography revealed a 20 mm polypoid tumor in the dilated distal bile duct, which exhibited early enhancement and papillary growth. Upper gastrointestinal endoscopy revealed mucus production from the papilla of Vater, characterized by its protruding and dilated orifice. Endoscopic ultrasonography visualized the polypoid tumor in the distal bile duct, but no invasive region was suggested by diagnostic imaging. Therefore, the initial diagnosis was IPNB. After endoscopic nasobiliary drainage, a pylorus-preserving pancreaticoduodenectomy was performed. Pathological examination of the resected bile duct revealed papillary proliferation of biliary-type cells with nuclear atypia, indicating pancreaticobiliary-type IPNB. In addition, solid portions comprised of tumor cells with characteristic salt-and-pepper nuclei were evident. Immunohistochemistry revealed expression of the neuroendocrine marker synaptophysin in this solid component, diagnosing it as a neuroendocrine tumor (NET). Furthermore, the MIB-1 proliferation index of NET was higher than that of IPNB, and microinvasion of the NET component was found, indicating neuroendocrine carcinoma (NET G3). This unique case of MANEC, comprising IPNB and NET, provides insight into the pathogenesis of biliary NET.

Urinary bladder urothelial carcinoma with expression of KIT and PDGFRA and showing diverse differentiations into plasmacytoid, clear cell, acantholytic, nested, and spindle variants, and into adenocarcinoma, signet-ring cell carcinoma, small cell carcinoma, large cell carcinoma, and pleomorphic carcinoma

Various tumors can arise in the urinary bladder (UB); most common is urothelial carcinoma (UC). UC of the UB have many variants. Other types of carcinomas such as adenocarcinoma (AC) and small cell carcinoma (SmCC) can occur in UB carcinomas. Expression of KIT and PDGFRA has not been reported. A 66-year-old man admitted to our hospital because of hematuria. Cystoscopy revealed papillary invasive tumor and a transurethral bladder tumorectomy (TUR-BT) was performed. The TUR-BT showed UC, AC, SmCC, large cell carcinoma (LCC), and pleomorphic carcinoma (PC). The UC component showed plasmacytoid, spindle, nested, clear cell, acantholytic variants. The AC element showed tubular adenocarcinoma and signet-ring cell carcinoma (Sig). Immunohistochemically, all of these subtypes were positive for cytokeratin (CK) AE1/3, CK CAM5.2, CK34BE12, CK5, CK6, CK7, CK8, CK18, CK19, CK20, EMA, CEA, p63, CA19-9, p53 (positive 45%), MUC1, NSE, NCAM, KIT, PDGFRA, and Ki-67 (87%). They were negative for vimentin, chromogranin, synaptophysin, S100 protein, CD34, CD14, α-smooth muscle actin, CD31, caldesmon, CD138, CD45, κ-chain, λ-chain, MUC2, MUC5AC and MUC6. Mucin histochemistry revealed mucins in AC element including Sig. A molecular genetic analysis using PCR-direct sequencing method identified no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The carcinoma was highly aggressive and invaded into muscular layer. The nuclear grade was very high, and there were numerous lymphovascular permeations were seen. The surface showed carcinoma in situ involving von-Brunn's nests. This case shows that carcinoma of UB can show diverse differentiations into numerous histological types and variants, and can express KIT and PDGFRA. The both genes showed no mutations in the present case.

Cutaneous hybrid tumor composed of epidermal cyst and cystic pilomatricoma expressing p53 and high Ki-67 labeling

Hybrid tumor composed of epidermal cyst and pilomatricoma has been reported in only four times in the English literature. Herein, a cutaneous hybrid tumor composed of epidermal cyst and cystic pilomatricoma in a 58-year-old woman was presented. The tumor was located in the scalp, and measured 1 x 1 x 1 cm. The tumor was cystic and contained atheromatous materials. Histologically, the cyst was composed of epidermal cyst (50% in area) and pilomatricoma (50% in area). The pilomatricoma was composed mostly of basophilic cells. Interestingly, the pilomatricoma element of the cyst showed immunoreactive p53 and Ki-67 (labeling=40%). In conclusion, the fifth case of hybrid tumor composed of epidermal cyst and pilomatricoma was presented.

Hints to the diagnosis of mixed acinar-endocrine carcinoma on pancreatic fine-needle aspiration: avoiding a potential diagnostic pitfall

BACKGROUND

Mixed acinar-endocrine carcinoma (MAEC) is a rare mixed tumor of the pancreas defined by both acinar and endocrine cell differentiation.

CASE

We present 2 cases of MAEC initially diagnosed as pancreatic endocrine neoplasm on fine-needle aspiration. Both patients were male, aged 51 and 75 years, and presented with 16-mm and 6-mm pancreatic masses, respectively. Aspirates showed loose aggregates and dispersed single plasmacytoid cells with moderate nuclear size variation, slightly irregular nuclear contours, fine to coarsely granular chromatin, occasional prominent nucleoli, and scant to moderate finely granular cytoplasm. Rare mitotic figures and pyknotic forms were noted in one of the cases. Endocrine differentiation was confirmed by immunocytochemistry which led to an initial diagnosis of pancreatic endocrine neoplasm. Trypsin and lipase immunocytochemistry were later obtained, confirming a component of acinar cell differentiation. Findings were confirmed on surgical excision.

CONCLUSION

Because of their potentially more aggressive clinical course and different therapeutic implications, MAECs are an important consideration in the differential diagnosis of pancreatic neoplasms. Certain cytomorphologic features and immunocytochemical markers of acinar cell differentiation may be helpful in raising the possibility of MAEC on cytology.

Leptomeningeal carcinomatosis as initial presentation in adenocarcinoma of lung with signet ring cell features: an autopsy case report

Signet ring cell (SRC) features are rare but well-recognized cytological changes of pulmonary adenocarcinoma (PA). PA with SRC features (PA-SRC) is frequently associated with anaplastic lymphoma kinase (ALK) gene rearrangement, and recognition of PA-SRC may be important for the administration of targeted treatment. To the authors' knowledge, leptomeningeal carcinomatosis (LMC) as an initial presentation of PA-SRC has not yet been reported. We report an autopsy case from a 59-year-old female who presented with intractable headache for 6 weeks and died of LMC as a result of metastatic PA-SRC. Premortem brain MRI showed nonspecific leptomeningeal enhancement. At autopsy, a tan rubbery mass was found in the hilar area of the right lung, which also surrounded the lower trachea and carotid arteries. A right posteromedial middle lobe mass was also found. Leptomeninges were slightly thickened, without discrete masses. Microscopic examination of the lung mass and leptomeninges showed solid sheets and nests of malignant cells with pleomorphic nuclei and frequent SRC features which comprised 50% of the mass. Immunohistochemically, the tumor cells demonstrated strong diffuse expression of cytokeratin (CK)-7, TTF-1, and napsin-A. Immunostains for CK-20 and ALK were negative. These features were consistent with PA-SRC. It has been reported that approximately 70% of PAs demonstrate ALK gene rearrangement when SRCs comprised >10% of the tumor cells. The presence of SRCs can be indicative of a lung primary and, because of frequent ALK gene rearrangement in PA-SRC, proper recognition of PA-SRC may be important in determining whether further testing is advisable (e.g., ALK immunostaining and/or ALK gene rearrangement).

The histogenic origin of melanoma arising in respiratory epithelium of a teratomatous germ cell tumor of the mediastinum: an enigma unraveled from an unlikely source

Mixed germ cell tumors are rare neoplasms that are known to occur in the anterior mediastinum. Characterized by two or more types of germ cell components, these tumors comprise upwards of 25% of mediastinal germ cell tumors. Even rarer are those harboring somatic-type malignancies such as carcinoma, sarcoma, and hematopoietic malignancies. To date, however, there are no known cases of melanoma arising in a malignant mixed germ cell tumor of the anterior mediastinum. We describe the first case of malignant melanoma with spindle and epithelioid components arising from respiratory epithelium in a mediastinal malignant mixed germ cell tumor of a 32-year-old male. In addition, we also provide evidence supporting the theory of neuroendocrine cells as the origin of melanoma arising in the respiratory epithelium. This case emphasizes the need to carefully evaluate all germ cell tumors, not only for a myriad of benign embryological components, but also for malignancies arising in these components, as they might change the prognosis and patient's course of treatment. This microscopic approach should bring to light the diversity of mixed germ cell tumors in addition to somatic malignancies with corresponding biologic potentials.

Squamous cell carcinoma arising within verrucous carcinoma of the oral cavity: a case report

The author herein reports a case of squamous cell carcinoma (SCC) arising within verrucous carcinoma (VC) of the hard palate. An 84-year-old woman was admitted to our hospital complaining of oral discomfort. Oral examination revealed a pedunculated verrucous tumor (15 x 15 mm) in the hard palate. A biopsy revealed verrucous tumor. Resection of the lesion with wide margins was performed. Grossly, the palate tumor was pedunculated and verrucous, but a depressed area (8 x 7 mm) was recognized. Microscopically, the verrucous ares showed verrucous proliferation of squamous epithelium with little cellular atypia, and was interpreted as VC without invasion. The depressed lesion was obvious SCC with invasion. There were direct transitions between the VC and SCC. Immunohistochemically, the VC and SCC tumor cells were negative for human papilloma virus antigens. P53 protein was expressed in both VC and SCC, though the expression in SCC was much more strong and broad than that in VC. The Ki-67 antigen was also expressed in the VC and SCC, and Ki-67 labeling index ranged was 12% in VC and 64% in SCC. These findings indicate that SCC may arise within VC.

Ovarian cystic tumor composed of Brenner tumor and struma ovarii

Ovarian tumor composed only of Brenner tumor and struma ovarii is very rare; only 6 cases have been reported in the English literature, to the best of the author's knowledge. A 66-year-old woman underwent right oophorectomy because of torsion of right ovarian cyst. Macroscopically, the ovarian cyst was hemorrhagic and red. Cystic content was hemorrhagic fluid. Microscopically, the cyst walls were composed only of Brenner tumor (50% in area) and struma ovarii (50% in area). Hemorrhage and ischemic changes were seen. Other elements were not recognized. No malignant transformation was noted. These two elements were separately present, and no mergers between them were recognized. Immunohistochemically, the Brenner tumor element was positive for cytokeratins (AE1/3 and CAM5.2) and Ki67 (labeling=3%), but negative for thyroglobulin, TTF-1, p53, CA125, and vimentin. The struma ovarii element was positive for cytokeratins (AE1/3 and CAM5.2), thyroglobulin, TTF-1 and Ki67 (labeling=5%), but negative for p53, CA125 and vimentin. The findings suggests that there were cases of ovarian cyst composed only of Brenner tumor and struma ovarii, that such a case may be monodermal mature cystic teratoma or the Brenner tumor element was derived from surface epithelium in the preexisting struma ovarii, and that such a tumor manifest as cystic torsion.

Glioblastoma with PNET-like components has a higher frequency of isocitrate dehydrogenase 1 (IDH1) mutation and likely a better prognosis than primary glioblastoma

Glioblastoma with primitive neuroectodermal tumor-like components (GBM-PNET), a rare variant of glioblastoma, poses both diagnostic and therapeutic challenges. Ten patients with GBM-PNET were investigated with a median age of 51.5 years and the male to female ratio of 4:1. The majority of patients (7 out of 10) showed ring-enhancing lesions on magnetic resonance imaging (MRI), which is classic for GBMs. Restricted diffusion was noted in 7 cases where diffusion weighted imaging (DWI) was performed, which correlates with the presence of PNET-like components. CD56 and vimentin immunostaining made the diagnosis of GBM-PNET much easier. Vimentin strongly and diffusely highlighted the astrocytic components and was negative in PNET-like components, while CD56 was strongly and diffusely positive in both astrocytic and PNET-like components. Seven out of 9 cases were positive for p53 in both astrocytic and PNET-like components. Two out of 8 cases harbored isocitrate dehydrogenase 1 (IDH1) R132H mutation, while IDH2 R172 mutations were not identified. Three out of 10 patients had a median survival time of 17 months while the two patients, whose tumor carried IDH1 mutation, were still alive after 15 and 31 months of follow-up. Compared to primary GBMs, GBM-PNETs might have a better prognosis. Further large scale studies are necessary to confirm this observation.

An unusual case of colonic mixed adenoendocrine carcinoma: collision versus composite tumor. A case report and review of the literature

We report a case of collision tumor of the cecum in a 50-year-old woman and discuss the morphological criteria used for classifying mixed glandular-endocrine neoplasms of the digestive tract in a large series of reported cases. The cecal tumor showed clear geographic polarization, with no admixture or transition of the 2 neoplastic components. A lymph nodal metastatic deposit contained both tumors. Immunohistochemical stainings were consistent with the carcinomatous and carcinoidal nature of the 2 neoplasms, except for a minute area of carcinoembryonic antigen positivity in the carcinoid. A review of the literature shows that many mixed glandular-endocrine tumors of the digestive tract escape precise classification using established morphological criteria. Collision and composite tumors can share common histological and immunohistochemical features, including polyclonal metastases and carcinoembryonic antigen expression in the carcinoidal area. Mixed tumors of the cecum showing a collision-like morphology appear to behave more aggressively than other colonic adenoendocrine carcinomas.

Apocrine Mixed Tumors of the Skin With Architectural and/or Cytologic Atypia: A Retrospective Clinicopathologic Study of 18 Cases

We present a series of 18 atypical apocrine mixed tumors of the skin characterized by architectural and/or cytologic atypia but which nevertheless do not qualify these lesions as carcinomas. There were 15 males and 3 females, and all but 1 presented with solitary nodules ranging in size from 4 to 20 mm; 1 female had a large tumor of 12 cm. The tumors were preferentially located on the head area, especially the face (13 cases). Other locations included the lower extremities (3) and inguinal area (2). In all patients, surgical excision of the tumors was performed. Clinical follow-up was available in 11 cases and ranged from 1 to 24 years (mean 9.6 y; median 5 y). No recurrences or metastases were documented. Overall, the lesions manifested a rather benign architecture, usually with good circumscription, lack of capsular breach or hypercellularity; however, some asymmetry, focally irregular infiltrationlike or pushing tumorous borders were seen. Microscopically, 17 cases conformed to the so-called hyaline cell-rich variant and showed multinucleated, bizarre, hyperchromatic cells in hyaline cell areas that had a myoepithelial immunophenotype; in 1 case, atypical mitotic figures were noted. One case showed mild nuclear pleomorphism in the ductal component. Tumors were negative for p53, including bizarre giant cells that did not label with Ki-67. Ultrastructurally, hyaline cells exhibited features consistent with myoepithelial differentiation. Seven cases studied by immunohistochemistry proved negative for HER-2/neu (c-erbB-2) protein expression, and the HER-2/neu gene was not amplified by fluorescence in situ hybridization analysis in 5 cases tested. As controls, 4 authentic malignant mixed tumors were studied, but these likewise tested negative for HER-2/neu protein expression and showed no gene amplification; 1 malignant mixed tumor had polysomy 17. We conclude that some atypical cytoarchitectural features in apocrine mixed tumors, albeit worrisome, do not indicate a malignant change.

Benign mixed epithelial and stromal tumor of the kidney

A 51-year-old, perimenopausal, female patient with 1-month history of right flank pain who was diagnosed with a renal mass and underwent nephron-sparing partial nephrectomy is presented. The renal mass was found to be a benign, biphasic tumor composed of an epithelial component, consisting of ducts of variable size scattered within a mesenchymal component, composed of spindle cells arranged in sheets and fascicles. No atypia, mitosis, or necrosis was found. The spindle component shows desmin, smooth muscle actin, and estrogen and progesterone receptor positivity immunohistochemically. The diagnosis of benign mixed epithelial and stromal tumor of the kidney is rendered. No recurrent disease has been detected during 2 years of follow up.

Complex mammary tumours in the female dog: a review

Spontaneous mammary tumours are most frequently seen (apart from rodents) in women, female dogs and cats. The mammary gland is the most commonly affected organ for tumours in women and in female dogs. The mammary gland has a similar histology in the different species whereas the number of glands differs as well as the number of interlobular ducts that reach the nipple/teat. The parenchymatous tissue is composed of alveoli that turn into interlobular ducts. The whole ductal tree is outlined by a two-layered epithelium with the luminal epithelial cells adjacent to the lumen and the more sparse myoepithelial cells peripherally located to these. Different proteins such as growth factors regulate the mammary gland, as they do for all tissues in the body. In addition, sex hormones regulate the biology of the mammary gland. Oestrogen has the most pronounced effect on duct growth whereas progesterone promotes growth of the alveoli.

Mixed epithelial and stromal tumor of the kidney in a 12-year-old girl

Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare kidney neoplasm that almost exclusively occurs in perimenopausal women, and long-term estrogen replacement is relevant to its pathogenesis. Herein is described an atypical case of MESTK uncovered in a 12-year-old premenarcheal girl without a history of prior estrogen use. On surgical specimen it was found that the well-circumscribed tumor measuring 14 cm arose from the lower pole of the right kidney, showing solid and fibrous-cystic areas. Microscopically, it was composed both of epithelial structures similar to renal tubules and stroma comprising non-specific spindle cells. Some intratumoral tubules showed affinities to distal-nephron-specific lectins, and those immunoreactive for proximal-tubule-specific CD15 were also present. In addition, primitive ductal structures were reactive both for CD15 and lectins, but immature epithelial elements typical of nephroblastoma were absent. Spindle cells were positive for actin, desmin and vimentin, and expressed progesterone and estrogen receptors. The tumor was comparable with MESTK, although some epithelia were associated with the immunophenotype of proximal tubules. The patient was free of disease postoperatively for 40 months. In the present case, remnants of the primitive periductal mesenchyme might be promoted to neoplastic cells by a sex-steroid surge during puberty.

Primary gastrointestinal stromal tumor of the esophagus in an HIV-positive patient

We describe a rare case of malignant gastrointestinal stromal tumor (GIST) of the esophagus presenting in an HIV-positive man. Not only did the tumor arise from an unusual anatomic site for GIST, namely, the esophagus, but it also had a predominant epithelioid cell morphology that is uncommon and preferentially associated with aggressive behavior. Exhaustive immunohistochemical studies showed strong reactivities to the classic GIST marker, CD34, and to the current more sensitive and more specific GIST marker, CD117/ c-kit protein. This immunophenotype corresponded to that of stromal tumors arising in the more common sites like stomach and small intestine as well as to that of a reported series of esophageal GISTs in the general population. Mutations of the c-kit protein was detected in the tumor, confirming previous observations. This further documents that esophageal GIST and the more common benign esophageal spindle cell lesions are pathologically distinct entities and despite its rarity, esophageal GIST should be recognized by pathologists and clinicians. The occurrence of this tumor in an HIV-positive patient is coincidental, and it resulted in an extremely unusual metastatic site that has not been reported for GISTs.

Benign mixed epithelial and stromal tumor of the kidney (MEST) with cytogenetic alteration

Benign mixed epithelial and stromal tumor of the kidney (MEST) is a new, rare entity. These tumors are composed of two components: a stromal and an epithelial one. Clinical outcome is usually good, no specific cytogenetic alterations have been described up to now. We describe for the first time a case with translocation t (1; 19).

A case of salivary gland-type mixed tumor of the lung differentiating toward type II alveolar epithelial cells in glandular components with a literature review

Salivary gland-type mixed tumor primarily arising in the lung is extremely rare. We report here a case of this type of tumor that occurred in the periphery of S4 of the right middle lobe in a 74-year-old man. Light-microscopically, this lung tumor, 15x9mm in size, exhibited almost the same features as those of mixed tumor of the salivary gland intermingled with chondromyxoid stroma, glandular component, solid growth pattern of myoepithelial components and well-developed cartilage formation, exhibiting a sharp margin. Immunohistochemical study revealed that the glandular components in the tumor was positive for thyroid transcription factor-1, TTF-1, a marker of epithelial cells of the thyroid as well as the lung. Furthermore, surface lining cells of the glandular components and luminal contents were positive for surfactant apoprotein A, PE-10, used as a marker of type II alveolar epithelial cells. These findings clearly demonstrate for the first time that glandular epithelial cells in the present salivary gland-type mixed tumor exhibited differentiation toward type II alveolar epithelial cells.

Nonepithelial neoplasms of the urinary bladder

Nonepithelial tumors are rare in the urinary bladder, but their exact classification is very important in the differential diagnosis between these tumors and epithelial lesions. In the new WHO classification and in the third series of the Armed Forces Institute of Pathology (AFIP) "Atlas of Tumor Pathology" on urinary bladder tumors, various mesenchymal tumors, mixed epithelial and mesenchymal tumors and myofibroblastic proliferations are summarized. In the following we will describe the histology, immunohistology, and cytogenetics of nonepithelial tumors and lesions.

Mixed tumors, myoepitheliomas, and oncocytomas of the soft tissues are likely members of the same family: a clinicopathologic and ultrastructural study

Four diagnostically unusual soft tissue tumors are presented. All lesions were of consistent size and long duration. Histologically, one lesion was analogous to mixed tumors of the usual sites (i.e., salivary glands), one lesion was totally spindled, and the two other lesions both had oncocytic appearances (epithelioid and spindle biphasic pattern in a case, purely epithelioid in the other). Immunohistochemically, the mixed tumor was positive for vimentin, cytokeratins, S-100 protein, and focally for EMA. The purely spindled tumor exhibited immunoreactivity for vimentin, actins, S-100 protein, EMA (focally), and GFAP. The oncocytic biphasic tumor was positive for mitochondrial antigen, vimentin, and actins. The purely epithelioid oncocytic neoplasm was immunoreactive only for mitochondrial antigen and vimentin. Ultrastructurally, in the epithelial-like portion of the first (mixed) tumor, peripheral arrays of contractile filaments were detected along with well-developed desmosomes. In the second (spindled) case, peripheral contractile filaments and attenuated desmosomes were also seen. In the third case, a huge number of mitochondria, some desmosomes, and actin-type microfilaments were found. In the fourth case, desmosomes and punctate subplasmalemmal densities, in addition to numerous mitochondria, were documented. In all cases an external basal lamina were present, which was discontinuous in the first three cases and almost continuous in the fourth. These tumors were respectively designated as mixed tumor, myoepithelioma of the classic type, myoepithelioma of oncocytic type with biphasic cell architecture, and true oncocytoma. So far, all tumors have followed benign clinical courses (median follow up: 12 months). Comparisons with similar tumors of other sites are drawn, and suggestions for considering all of them as members of the same myoepithelial-derived tumor family are given.

Immunohistochemical evaluation of PCNA and Ki-67 in ameloblastoma

Thirty-two ameloblastoma tissues were immunohistochemically studied using monoclonal anti-proliferating cell nuclear antigen (PCNA) and anti-Ki-67 antibodies. Positive cells were evaluated and analyzed in relation to the WHO classification, cytological pattern of the outer layer cell, clinical appearance, tumor location, radiographic appearance and patient's age. In regard to the cytological pattern of the outer layer cells, the basal cell type had significantly higher PCNA and Ki-67 (P<0.05) labeling indices than the cuboidal cell type. The solid type had significantly higher PCNA and Ki-67 (P<0.05) labeling indices than the cystic and the mixed type. The labeling index of the younger patient was found to be the lowest, the middle age was in the middle and the older patient was the highest. These results indicated that the proliferating activities of ameloblastomas are quite variable, and the evaluations of Ki-67 and PCNA seem to be good indicators to assess the proliferating activity of each type of ameloblastomas.

Benign renal angiomyoadenomatous tumor: a previously unreported renal tumor

We describe a unique benign tumor of the kidney in a 93-year-old man. Microscopically the tumor was composed of an intimate intermixture of epithelial component and smooth muscle tissue, which formed the stroma of the tumor. In some parts the epithelial cells in adenomatous tubular formations were endowed with clear snouts. These clear snouts had a blister-like quality and grew on the secretory cells lining the tubules. No atypias, mitoses, or pleomorphism were present in the tumor. The muscular component consisted of poorly cellular, HMB-45-negative, leiomyomatous bundles, which greatly differed from that of angiomyolipoma. It encircled the whole tumor and intimately intermingled with the epithelial component. These leiomyomatous bands formed focally abortive vessels, which had incomplete and irregular walls and lacked an elastic layer. Even more interesting was a peculiar vascularization of the tumor. All epithelial tubular structures of the tumor revealed an intimate association with small capillaries. A fine labyrinth of the capillaries rimmed the rows of the epithelial cells. To the best of our knowledge this tumor differs from all previously described.

Mixed epithelial and stromal tumor of the kidney

We describe the clinicopathologic features of 12 patients with a distinctive tumor of the kidney characterized by a mixture of epithelial and stromal elements that form solid and cystic growth patterns. Similar tumors were reported previously in the literature under various names, including adult mesoblastic nephroma. All but one of the patients were women. The only man had a long history of treatment with lupron and diethylstilbesterol. Seven of the women had histories of long-term oral estrogen use of whom six had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy several years prior, and the seventh patient had been using oral contraceptives for many years. Another woman had this operation but did not receive any hormone therapy. Ages ranged from 31 to 71 years (mean, 56 yrs). Six patients presented with symptoms, including pain and infections attributable to mass effect, and in six the tumor was detected incidentally. Grossly, the tumors were well-circumscribed (mean size, 6 cm; range, 3-12 cm) and consisted of solid and cystic components, most often in equal proportions but in variable distribution. Microscopically, the spindle cell component ranged in appearance from scar-like fibrous tissue to leiomyoma-like interlacing fascicles; usually there was a mixture of both. More cellular foci reminiscent of ovarian stroma or solitary fibrous tumor were also present. No blastema was present. Epithelial elements (composed of clusters of tubules with variable lining) were scattered amidst the spindle cells, and focally transformed into large cysts lined by cells with abundant pink cytoplasm and a hobnail appearance. Immature epithelial elements typical of Wilms' tumor were not present. Muscle markers (desmin and smooth muscle actin) were positive diffusely and strongly in the spindle cells of all tumors, whereas HMB-45 and CD34 were absent. Estrogen receptors were detected in the nuclei of spindle cells in seven tumors and progesterone receptors in three. The distinctive clinicopathologic characteristics of these lesions warrant their classification as a separate category of kidney tumor. We suggest the descriptive term "mixed epithelial and stromal tumor" for this group until its nature and relationship to other kidney lesions are further clarified. Its preponderance in females with a history of long-term estrogen replacement and the history of long-term sex-steroid use in the only male patient, combined with the frequent content of estrogen and progesterone receptors in the spindle cells, suggest that the hormonal milieu plays a role in the evolution of these tumors. The clinical and pathologic parallels with mucinous cystic tumors of pancreas and liver raise the possibility of a common pathogenetic mechanism that may be linked to the periductal fetal mesenchyme. We think this entity is a benign composite neoplasm in which stroma and epithelium are both integral neoplastic components.

Divergent differentiation in neuroendocrine tumors of the adrenal gland

Composite tumors of the adrenal medulla usually consist of pheochromocytoma admixed with ganglioneuroma or ganglioneuroblastoma. These neoplasms reflect phenotypic plasticity shown by primitive sympathetic cells and mature chromaffin cells in vitro. They may give rise to metastatic neuroblastoma in adults and may cause signs and symptoms attributable to both catecholamine and neuropeptide production. Schwann cells and sustentacular cells are typically numerous in these tumors but it is not known whether they are neoplastic. Immunohistochemical staining for catecholamine biosynthetic enzymes, secretory vesicle proteins and S-100 protein tends to recapitulate staining of the normal adrenal medulla or sympathetic ganglia. Sparsity of chromogranin A in the cell bodies of immature and mature neurons is a diagnostically useful characteristic.