Carcinoma of the colon with undifferentiated, carcinoid, and squamous cell features

Primary colonic squamous cell carcinoma: a case report and review of the literature

Colonic squamous cell carcinoma is extremely rare, with no clear pathogenesis. It usually presents as an emergency. We present the surgical management of a descending colon squamous cell carcinoma, together with a review of the available cases of colonic squamous cell carcinoma in the literature. A 69-year-old woman presented with a palpable mass and abdominal pain. She underwent ultrasound and colonoscopy, which revealed a large obstructing mass at the descending colon, the biopsies of which were not diagnostic. Unfortunately, she was readmitted with bowel obstruction and underwent extended right hemicolectomy with en-bloc excision of attached small bowel and omentum because of local mass expansion. Histopathological analysis demonstrated squamous cell carcinoma with lymph node metastases. Palliative chemotherapy followed, owing to liver and peritoneal deposits. Sixty-six cases of colonic squamous cell carcinoma have been reported in the literature. The most common location is the right colon. Most cases present at a late stage. Several theories for the pathogenesis of colonic squamous cell carcinoma have been reported; the most popular is the squamous transformation of a pluripotent stem cell.

Neoplastic Colonic Polyp with Extensive Squamous Metaplasia. Case Report

Extensive squamous metaplasia in neoplastic colonic polyps is rare. This paper describes extensive squamous metaplasia in an adenomatous polyp evolving into adenocarcinoma. The origin of squamous cell carcinoma and adenocanthoma of the colon is not well understood. This case is the only case reported in the literature that demonstrates the development of squamous metaplasia in dysplastic colonic glands, in situ adenocarcinoma, and finally invasive adenocarcinoma of the colon. The pertinent literature is reviewed.

Squamous cell carcinoma of rectum presenting in a man: a case report

BACKGROUND

Primary squamous cell carcinomas of the colorectum are very uncommon. Until now, to the best of our knowledge, only 114 cases of squamous cell carcinoma in the colorectum exist in the reported literature. Here we report a case of squamous cell carcinoma of the rectum in the ethnic Kashmiri population in northern India.

CASE PRESENTATION

The case of a 60-year-old male patient (Asian) with a pure squamous cell carcinoma of the rectum is presented here. The patient underwent a curative surgery with concomitant chemotherapy. Two years after the initial curative resection of the tumor he is still alive.

CONCLUSION

The prognosis for squamous cell carcinoma of the colorectum is worse than for that of adenocarcinoma, because of the delayed diagnosis. The etiopathogenicity of squamous cell carcinoma of the colorectum is discussed. Surgical resection of the lesion seems to be the treatment of choice. Chemotherapy also helps in improvement of the prognosis.

Squamous cell carcinoma of the rectum 21 years after radiotherapy for cervical carcinoma

Squamous cell carcinoma (SCC) of the rectum is an extremely rare malignancy, accounting for 0.1-0.2% of rectal malignancies. It is associated with ulcerative colitis, prior radiation, schistosomiasis, ovarian cancer, endometrial cancer, human papilloma virus, colocutaneous fistulas and colonic duplication. Prior reported cases of SCC of the rectum have involved treatment with brachytherapy and external beam radiation. This case is particularly interesting because of the remote exposure of radiation (21 years previously) and the subsequent development of SCC of the rectum. Although extremely rare, SCC of the rectum can occur decades after radiation exposure.

Squamous cell carcinoma of the rectum in ulcerative colitis: case report and review of the literature

The majority of colorectal carcinomas diagnosed are adenocarcinomas. Squamous cell carcinomas (SCC) of the rectum are rare tumors, and were reported as rare complication of inflammatory bowel disease. Surgery is the most effective therapy; and adjuvant chemotherapy and radiotherapy should also be considered. We report two cases of ulcerative colitis-associated SCC of the rectum. The lesions were treated with chemoradiotherapy with complete response.

Squamous cell carcinoma of the rectum: a case report and review of the literature

Squamous cell carcinoma of the colon and rectum are extremely rare neoplasms. Many questions regarding their histogenesis and biological behaviour remain unanswered. Surgery is the most effective therapy, and adjuvant chemotherapy and radiotherapy should be considered, especially for node-positive patients. We present a patient with squamous cell carcinoma of the middle rectum who underwent abdominoperineal resection and postoperative adjuvant chemotherapy. The pertinent literature is reviewed.

Heterogeneous expression of neuroendocrine marker proteins in human undifferentiated carcinoma of the colon and rectum

The expression of neuroendocrine marker proteins in undifferentiated colorectal cancers has not yet been studied in great detail. Therefore, the survival of 20 patients with small cell undifferentiated colorectal cancers treated at our institution between 1982 and 1997 (0.8% of all operated colorectal carcinomas) was correlated with the extent of neuroendocrine differentiation. Chromogranin A, synaptophysin, syntaxin1, VAMP2, SNAP25, and alpha/beta-SNAP were used as neuroendocrine markers. Based on the degree of immunoreactivity for these marker proteins, tumors were divided into group 0 (<2% cells stained positive for neuroendocrine markers) and group 1 (>2% cells stained positive). Patients were followed up for at least 5 years or until death. Nine of twenty (45%) undifferentiated colorectal tumors expressed neuroendocrine markers (group 1). Only one patient of this group survived 2 years (11%), whereas the 2-year survival rate was 45.4% in group 0. Nine of eleven patients of group 0 were diagnosed in UICC stage I-III, whereas eight of nine tumors with expression of neuroendocrine markers were diagnosed in UICC stage IV (P = 0.002). Our results show that neuroendocrine differentiation is often seen in small cell undifferentiated colorectal cancer. It correlates with a more aggressive course of the disease.

Diagnostic and pathogenetic implications of colorectal carcinomas with multidirectional differentiation: a report of 4 cases

Multidirectional differentiation in colorectal carcinomas is a rare phenomenon. Four cases are reported herein, and their clinical and pathologic characteristics are discussed. Two men and 2 women between the ages of 56 and 76 years who presented with abdominal symptoms are included in this report. Two tumors were located in the right colon, one in the splenic flexure, and one in the descending colon. Distant metastases were evident at presentation in 3 of 4 cases. Histologically, two tumors exhibited neuroendocrine and glandular differentiation; the third tumor was an adenocarcinoma with a sarcomatous component and the fourth tumor showed 3 lines of differentiation (glandular, squamous, and sarcomatoid). In all tumors evaluated, areas of adenocarcinomas were positive for low-molecular weight cytokeratin (CAM 5.2) and mucicarmine, but negative for high-molecular weight cytokeratin (AE3). The squamous cell component was AE3 positive and CAM 5.2 negative. The neuroendocrine component was highlighted by neuroendocrine markers and the sarcomatoid component revealed smooth muscle differentiation. All tumors (except one mucinous tumor) were negative for cytokeratin-20 staining. One patient was on supportive care for terminal metastatic carcinoma, and 2 patients were being treated with adjuvant chemotherapy at the time of this report. Colon carcinoma with multidirectional differentiation is a rare event and may originate from stem cells within the gastrointestinal mucosa, and/or represent the convergence of multiple tumors arising at the same site. This type of tumor should be considered in the differential diagnosis of a bowel biopsy with multiple histopathologic variants.

Malignant islet cell tumor with sarcomatous differentiation

Malignant mesenchymal neoplasms of the pancreas are rare and malignant islet cell tumors with sarcomatous dedifferentiation are rarer still. We present a case of malignant islet cell tumor with sarcomatous differentiation, which to our knowledge is only the second reported case showing such a combination of morphologic features. Clinically, the neoplasm was not hormonally active and immunohistochemical staining was negative for gastrin, glucagon, insulin and somatostatin. The sarcomatous component strongly reacted with an antibody directed against vimentin, and a minority of cells stained strongly with antisera directed against desmin and smooth muscle actin. The spindle cell component was nonreactive with antibodies directed against Factor VIII. The myogenous direction of differentiation in the present tumor is similar to that seen in the prior case report of malignant islet cell tumor with rhabdomyosarcomatous differentiation.

Adenosquamous carcinoma of the rectum showing endocrine-cell differentiation: report of a case

PURPOSE

Previous records of adenosquamous carcinomas with endocrinologic features rarely have been reported. Although the disease behaves in an extremely aggressive manner, chemotherapy after surgery has never been proposed. We used regional chemotherapy for treatment of unresectable liver metastases.

METHODS

Hartmann colostomy was performed and 5-fluorouracil was infused into the hepatic artery for 15 weeks after the operation.

RESULTS

Multiple liver metastases were present at the initial operation. Three months after the start of the chemotherapy, computed tomography showed that metastatic tumors in the liver had disappeared. The patient survived 18 months after the initial operation.

CONCLUSION

This case report describes the first successful treatment with adjuvant regional chemotherapy of a patient who had an adenosquamous carcinoma with endocrine-cell differentiation in the rectum and liver metastases.

Adenosquamous carcinoma of the small intestine. Report of a case and review of the literature

Primary adenosquamous carcinomas of the intestine are rare tumors, particularly those occurring in the small bowel. We report the third case of an adenosquamous carcinoma of the ileum in a 55-year-old-man. Histologically, the tumor consisted of malignant glandular and squamous elements. A review of the literature is presented.

Squamous-cell carcinoma of the colon responsive to combination chemotherapy: report of two cases and review of the literature

PURPOSE

The majority of colorectal neoplasms diagnosed are adenocarcinomas. Other histologies such as squamous, adenosquamous, carcinoid tumors, or lymphoid tumors are occasionally identified. Given the rarity of squamous-cell tumors, it is very difficult to study their natural course and response to therapy. An attempt is made to describe the frequency, anatomic location, and response to therapy with a review of the literature.

METHODS

From the Cancer Registry at the University of Missouri-Columbia Ellis Fischel Cancer Center, tumors of the colon identified above the dentate line were selected for chart review. Data were extracted from cases between the years 1940 and 1996. The key terms used to identify cases were epidermoid, squamous cell, and cancer of the rectum or colon. Using this approach, forty patients were identified and each record was reviewed.

RESULTS

The majority of these cases were anal cancers with proximal extension into the rectum and were excluded. Of 4,561 cases of epithelial colon and rectal cancers identified, only one additional case of squamous-cell cancer could be verified. In this report we describe a patient with a primary squamous-cell carcinoma of the sigmoid colon with metastatic disease to the liver at diagnosis who responded to systemic chemotherapy. We believe this to be the first reported case of this rare tumor type in which the patient's tumor responded to systemic chemotherapy. Two cases with a thorough review of literature are presented.

CONCLUSIONS

Primary squamous-cell carcinoma of the colon is a rare malignancy of unknown cause and pathogenesis. Metastatic tumors to the colon should be ruled out in all cases before therapy. Early detection and surgery remain the main therapeutic options, but as presented in our case, response to chemotherapy in advanced disease is encouraging.

Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas

BACKGROUND

The histopathologic spectrum of colorectal neuroendocrine tumors ranges from benign to highly malignant. In this spectrum, poorly differentiated neuroendocrine carcinoma (PDNC) is the most aggressive type, characterized by early dissemination and a rapidly fatal course. Since it is unclear whether PDNC originates from neoplastic transformation of preexisting neuroectodermal cells, pluripotent epithelial stem cells, or adenocarcinoma precursor cells, we investigated the histogenesis of this type of cancer by performing genetic analyses on a series of colorectal tumors.

METHODS

Archived histologic sections of colorectal PDNC from nine patients were analyzed; gastrointestinal carcinoid tumor specimens from four patients were used as controls. The specimens were deparaffinized, microdissected, and analyzed genetically. After DNA extraction, polymerase chain reaction amplification was performed to investigate alteration (i.e., loss of heterozygosity [LOH]) of the APC (adenomatous polyposis coli), DCC (deleted in colorectal carcinoma), and p53 (also known as TP53) genes.

RESULTS

LOH of the APC, DCC, or p53 genes was observed in six of eight informative PDNC tumors; no LOH was detected in the carcinoid control specimens. Four of five informative PDNC tumors had associated adenocarcinoma; LOH of the APC and p53 genes in these tumors involved the same allele in both tissue components. Four of the five tumors with associated adenocarcinoma showed LOH of the DCC gene; in three of these four tumors, the PDNC and adenomatous components showed LOH of the same allele.

CONCLUSIONS

PDNC and associated adenocarcinoma appear to be derived from the same cell of origin, which is most likely either a pluripotent epithelial stem cell or an adenocarcinoma precursor cell.

Anaplastic carcinoma of the colon: clinicopathologic study of eight cases of a poorly recognized lesion

Eight cases of a distinctive histological variant of bowel cancer characterized by an anaplastic morphology were identified from 2,650 colonic malignancies (0.3%). The tumors were histologically composed of sheets of anaplastic tumor cells with frequent atypical mitoses, absence of gland formation, and mucicarmine and periodic acid-Schiff (PAS) negativity. Positive immunostaining for cytokeratin and vimentin was observed in eight cases and for epithelial membrane antigen in three; whereas carcinoembryonic antigen, alpha-fetoprotein, S-100 protein, HMB-45 antimelanoma antigen, leukocyte common antigen, and neuroendocrine markers were uniformly negative. Ultrastructural examination demonstrated intercellular tight junctions, focal surface microvilli, and apical terminal webs or long rootlets of microfilaments supporting a colonic derivation. At the time of diagnosis, metastases to regional lymph nodes were found in seven cases and to the liver in six. All patients in this study died of tumor within 9 months. This report emphasizes a poorly recognized variant of colonic carcinoma, characterized by a high degree of anaplasia and malignant behavior. The differential diagnosis for these lesions is discussed.

Fine-needle aspiration cytology of metastatic small cell carcinoma of the colon: a report of three cases

Small cell carcinoma of the large intestine is a rare, extremely aggressive malignancy often associated with an overlying adenoma. We report three cases of metastatic small cell carcinoma of the colon diagnosed by fine-needle aspiration (FNA) biopsy. Two of the patients were women (ages 33 and 46 yr old) and one was a man (69 yr old). FNA biopsy established the diagnosis of metastatic small cell carcinoma involving the liver (2 cases) and soft tissue of the scapular region (1 case). In one patient, the FNA diagnosis of hepatic metastases preceded identification of the primary site. Subsequently, the patient was found to have a small cell carcinoma subadjacent to a colonic villous adenoma, illustrating the importance of investigating villous lesions of the colon in patients with metastatic small cell carcinoma of unknown primary origin (especially in non-smokers). All three cases showed the characteristic cytologic features of small cell carcinoma. Ancillary studies performed on aspirated material confirmed the diagnosis of small cell carcinoma in one case. Immunocytochemical studies revealed punctate cytokeratin and diffuse neuron-specific enolase (NSE) positivity of the malignant cells. Ultrastructurally neurosecretory granules were evident. To the best of our knowledge, this is the first FNA cytologic report of metastatic small cell carcinoma of the large intestine. This FNA report also demonstrates when a small cell carcinoma is detected in a metastatic site in a patient lacking a lung primary, a likely primary site could be adjacent or beneath a polypoid lesion of the colon.

Small cell neuroendocrine carcinoma of the rectum

Poorly differentiated small cell neuroendocrine (NE) carcinoma of the colon and rectum is a rare primary epithelial malignancy at this location. A case of a highly aggressive NE tumor of small cell type, combined with non-invasive well-differentiated papillary adenocarcinoma in villous adenoma is reported. The patient died rapidly with massive and progressive liver metastasis. The tumor cells were argyrophilic and diffusely immunoreactive for neuronspecific enolase and synaptophysin. Ultrastructural analysis disclosed NE-type cored granules in most of the small tumor cells. NE tumors of the colon and rectum are briefly reviewed.

Carcinomas of the colon with multidirectional differentiation. Report of two cases and review of the literature

Two cases of colonic carcinomas with multidirectional differentiation are presented. Both tumors showed light microscopic and immunohistochemical evidence of areas of adenocarcinomatous, squamous cell carcinomatous, and neuroendocrine differentiation. Only six similar cases have been previously reported. These highly malignant tumors support the recent concept of a multipotential stem cell within the mucosa of the gastrointestinal tract capable of differentiation in several directions.

Gastrointestinal neuroendocrine cell proliferations

The gastrointestinal neuroendocrine cell proliferations are comprised of a few hyperplasias and various neoplasias. The better characterized hyperplasias include G-cell hyperplasia, either primary or secondary, enterochromaffin-like (ECL)-cell hyperplasias, generally secondary to hypergastrinemia, and EC-cell hyperplasias. The neoplasias include carcinoid tumors, demonstrating low malignancy and divided into foregut, midgut, and hindgut varieties, poorly differentiated neuroendocrine carcinomas resembling their pulmonary counterparts the "oat cell" carcinomas both in histological pattern and in their highly malignant behavior mixed endo-exocrine tumors, which in turn can be divided into composite tumors formed by a population of endocrine cells and a population of exocrine cells, and amphicrine tumors formed by a uniform population of cells with a mixture of endocrine and exocrine phenotypic traits. Although some of these mixed tumors show a degree of malignancy intermediate between the classical carcinoid and an adenocarcinoma, more information must be gathered to establish firm prognostic parameters for these relatively new entities.

Composite glandular-carcinoid tumour of the terminal ileum

AIMS

To investigate a female patient with a tumour mass of the terminal ileum, to define the nature of the tumour, and to correlate its morphology and behaviour with similar types of tumours of the large intestine and stomach.

METHODS

Tissues obtained at colonoscopy, from hemicolectomy specimens, and from liver and peritoneal biopsy specimens were studied macroscopically, microscopically, histochemically, and immunohistochemically for epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), neuron specific enolase (NSE), and S100 protein.

RESULTS

Macroscopic examination showed a tumour of the terminal ileum protruding into the caecum. Microscopically the tumour showed two components, one adenoma with moderate dysplasia and the other carcinoid tumour. The adenomatous component stained positively for EMA and CEA and negatively for NSE. The carcinoid component stained positively for NSE and negatively for EMA and CEA. Histochemically the carcinoid area was argyrophil positive and argentaffin negative. Only the carcinoid had metastasised, to the liver, peritoneum, and the lymph nodes, at the time of diagnosis.

CONCLUSION

The morphological, histochemical, and immunohistochemical findings confirm the diagnosis of a composite adenoma-carcinoid tumour of the terminal ileum.

Tripartite differentiation in a carcinoma of the duodenum

BACKGROUND

Carcinomas containing three distinctly different cell lines have been encountered in the colon and rectum, but a tripartite malignancy in the small intestine has not been reported previously.

METHODS

A duodenal carcinoma was studied by light and electron microscopic examination and immunohistochemistry.

RESULTS

The duodenal carcinoma was found to have tripartite glandular, squamous, and neuroendocrine differentiation. Histologically, an adenocarcinoma, which originated in a villous adenoma, was continuous with squamous cell carcinoma and small cell carcinoma components. Tumor cells of the squamous cell carcinoma component had conspicuous intercellular bridges but did not form keratin pearls. Immunohistochemical analysis showed strong expression of carcinoembryonic antigen (CEA) by the adenocarcinomatous component. The squamous cell carcinoma component demonstrated focal weak CEA and neuron specific enolase (NSE) reactivity. Ultrastructurally, tumor cells of this component had frequent desmosomes and free tonofilaments. The small cell carcinoma had clusters of dense core granules in tumor cell cytoplasmic processes, which are indicative of neuroendocrine differentiation. This neuroendocrine component was immunoreactive for somatostatin and NSE.

CONCLUSIONS

This case of tripartite duodenal carcinoma supports the theory of an origin from an intestinal pluripotential stem cell capable of differentiating into multiple cell types.

Nonpulmonary small cell carcinomas of extragenital origin metastatic to the ovary

Seven small cell carcinomas of extragenital and extrapulmonary origin that metastasized to the ovary are described. The tumors occurred in women who were 21-77 years of age (mean, 49 years) and were discovered at, or close to, the time of presentation. The primary sites were the intestine (three cases), thymus (two cases), and inguinal skin (one case), and in one case it was undetermined. The ovarian tumors, four of which were bilateral, ranged from 1.2 to 25 cm in diameter (mean, 11 cm). Microscopic examination showed typical features of small (oat) cell carcinoma in six cases; one neoplasm resembled a small cell carcinoma of intermediate cell type and contained rare glands. On immunohistochemical examination, six of six tumors stained for cytokeratin, five of five for neuron-specific enolase, two of six for chromogranin, and none of four for vimentin. The primary cutaneous tumor was a Merkel cell carcinoma. The patient with that case died at 8 months. Two patients with intestinal tumors died at 1 and 2 months, and one is free of disease at 4 years after receiving chemotherapy. Both patients with mediastinal tumors received chemotherapy; one died at 11 months and one had brain metastases at 5 months and was lost to follow-up. The final case is recent. The differential diagnoses in these cases include primary ovarian small cell carcinomas of hypercalcemic and pulmonary types and various other small cell malignant tumors metastatic to the ovary. Consideration of a variety of clinical and pathologic features should enable these important distinctions to be made.

c-myc antisense oligonucleotides inhibit the colony-forming capacity of Colo 320 colonic carcinoma cells

Colo 320 cells are colonic carcinoma cells known to express abundant c-myc mRNA. Based on the response of several hematopoietic cell lines to chemical inducers of differentiation, we reasoned that such agents might have similar inductive activity in Colo 320 cells. Accordingly, we exposed Colo 320 cells to 5 mM sodium butyrate (NaBT) for 7 d. C-myc expression decreased threefold and self-replicative potential decreased (defined as a greater than 60% decrease in colony-forming capacity in soft agar that did not contain inducer). In an effort to demonstrate a direct cause and effect between myc expression and the colony-forming capacity of Colo 320 cells, we exposed these cells to a 15-base antisense c-myc oligonucleotide (complementary to the translation initiation region of exon II). Cells were also exposed to equimolar (20 microM) amounts of sense and missense oligonucleotides. Subsequently, cells were incubated at 10, 20, 30, and 40 microM antisense DNA for 16 h, then washed and plated in oligonucleotide-free agar medium. We demonstrated that: (a) the oligomers were stable in the extracellular medium and in the cell cytoplasm; (b) the uptake of the oligonucleotides was 0.7%; (c) sense and missense oligonucleotides had no effect on colony-forming capacity; and (d) the antisense c-myc oligonucleotide resulted in a 40-75% concentration-dependent decrease in colony-forming capacity. The specific inhibition of colony-forming capacity by antisense DNA suggests that the role of myc expression in Colo 320 cells is similar to its role in hematopoiesis, and that the failure to inhibit myc expression maintains colony-forming capacity. This system provides a new strategy for inducing differentiation and may provide further insight into the genetic factors that govern the process of colonic carcinogenesis.

Extrapulmonary and pulmonary small-cell carcinoma: tumor biology, therapy, and outcome

Extrapulmonary small-cell cancer is a distinct clinicopathological entity from small-cell anaplastic carcinoma of the lung. Approximately 1,000 cases have been projected annually in the United States, which represents an overall incidence of between 0.1% and 0.4% of all cancer. Not surprisingly then, little information is available regarding the treatment of this disease, which presents a challenge to the clinician when it is regionally confined. The majority of patients with extrapulmonary small-cell neoplasms have only been treated with local modalities of therapy, surgery, radiation, or a combination of both. Prolonged survival is not infrequent, which is in contrast to the experience for small-cell lung cancer and surprising given our current systemic approach to patients with this disease. This report will summarize the similarities and differences in biology, natural history, and clinical characteristics of patients with extrapulmonary small-cell cancer and small-cell anaplastic carcinoma of the lung. The histogenesis of small-cell cancer is briefly reviewed. A general therapeutic approach to patients with small-cell lung cancer is reported. Lastly, recommendations for therapy of patients with regionally confined extrapulmonary small-cell cancer by primary site are outlined.

Small-cell carcinoma of gallbladder. An immunocytochemical and ultrastructural study

An unusual carcinoma of the gallbladder in a seventy-one-year-old woman displayed features of a well-differentiated adenocarcinoma, atypical carcinoid and small cell undifferentiated carcinoma. The patient died from progressive hepatic failure four months after surgery. Autopsy showed bulky liver masses and several peritoneal nodules exclusively composed of small, hyperchromatic cells. The neuroendocrine nature of the small cell component of the tumor was documented by the presence of neurosecretory granules at the ultrastructural level and by immunocytochemical positivity to NSE and Synaptophysin. The epithelial markers, cytokeratin and CEA, were also positive in the carcinoid and in the undifferentiated portions of the tumor. A common endodermal origin is suggested for carcinoid and small cell carcinoma of the gallbladder.

Small cell undifferentiated ('neuroendocrine') carcinoma of the colon

Three patients are described who presented with a large colonic adenoma in which a solid, undifferentiated carcinomatous component was found on microscopic examination. Despite small size (1.0 and 1.5 cm) and submucosal location in two cases, the tumours had metastasized to regional lymph nodes and the liver and death ensued at 4, 11 and 18 weeks after surgery. Immunocytochemistry was positive for carcino-embryonic antigen, low molecular weight cytokeratins and neuron specific enolase in all three cases and scanty dense core granules of neurosecretory type were found in one of two examined by electron microscopy. These 'neuroendocrine' carcinomas are compared with 'pure' adenomas and 'ordinary' poorly differentiated adenocarcinomas of the colon from which they differ, mainly by lack of glandular differentiation and mucus secretion, although two adenocarcinomas also showed patchy reactivity for neuron specific enolase. The term 'neuroendocrine' may be disputed but is now well established to describe a tumour that runs a uniquely aggressive course and for which radical surgery alone cannot provide a cure.

Small cell carcinoma of the stomach. Case report and review of the literature

Small cell carcinoma of the stomach is an unusual and rare neoplasm with only eight reported cases in the world literature. Like small cell carcinomas elsewhere, they possess rapid growth ability and high propensity to metastasize with short survival. Clinically, small cell carcinoma is indistinguishable from adenocarcinoma. Because of the rarity of gastric small cell carcinoma, there is minimal information available on the optimal treatment. Herein, we report on a patient with metastatic pure small cell carcinoma of the stomach. He underwent palliative surgery and postoperative combination chemotherapy with transient partial response. He died 10 months after diagnosis with progressive widespread disease.

Cell lineage markers in premalignant and malignant colonic mucosa

Normal colonic epithelial cells consist of several cell types or lineages that are thought to arise from a common stem cell precursor. Neoplastic transformation may occur at different stages in the differentiation of a colonic stem cell to produce tumors that may retain characteristic cell lineage phenotypes. In this study, immunohistochemical techniques were used to identify cell lineage-related markers in fetal, normal, hyperplastic, adenomatous, and cancerous colonic tissue. These markers consisted of secretory component (columnar cells), a purified mucin antigen (mucous or goblet cells), chromogranin A (enteroendocrine cells), lysozyme (Paneth cells), and carcinoembryonic antigen (panepithelial cell marker). Colonic neoplasms, like normal mucosa, predominantly expressed the markers of columnar and goblet cell lineages. Chromogranin A was expressed in a small population of cells in most normal and fetal colonic crypts. Chromogranin A reactive cells were found in 55% of hyperplastic polyps, 31% of adenomatous polyps, and 33% of carcinomas. Lysozyme reactivity was rare in fetal, normal, and hyperplastic specimens, but was present in 86% of adenomas and 40% of carcinomas. Of 42 primary carcinomas, 9% were "pluripotent" and expressed markers of all four cell lineages. In addition to columnar and goblet cell markers, 7% expressed both enteroendocrine and Paneth cell markers, 17% expressed enteroendocrine cell markers, and 24% expressed Paneth cell markers. Two cases (5%) lacked expression of any of the cell lineage markers. The remainder expressed only columnar and goblet cell markers. The markers used in this study appear to identify the major cell lineages of fetal and normal colonic epithelium and can be used to delineate the altered cell lineage phenotypes in premalignant and malignant colonic mucosa.

Adenosquamous carcinoma of the colon--an immunocytochemical and ultrastructural study. Report of two cases and review of the literature

This paper presents two cases of adenosquamous carcinoma of the colon and brings to 39 the total number documented in medical literature. The concurrent glandular and squamous differentiation of the tumor cells was demonstrated by immunocytochemistry and electron microscopy. Evaluation of the biologic characteristics of all the reported cases suggests that malignant squamous elements in colonic carcinomas behave more aggressively than their glandular counterparts. In contradistinction from the pure squamous-cell carcinoma of the colon, adenosquamous carcinoma does not show the same predilection for the right colon.

Humoral hypercalcemia complicating adenosquamous carcinoma of the proximal colon

Hypercalcemia as a complication of carcinoma of the colon is uncommon (1). It usually occurs in the presence of anorectal or rectal carcinoma that metastasizes to the lumbosacral vertebrae (2-4). Hypercalcemia complicating colon carcinoma in the absence of bone metastases--so-called humoral hypercalcemia of malignancy or paraneoplastic hypercalcemia--is rare. Only two such cases associated with adenocarcinoma of the colon (5,6) and two cases associated with adenosquamous carcinoma of the distal colon (rectum and sigmoid) (7) have been reported. We describe the first reported case of an adenosquamous carcinoma of the cecum and ascending colon that was accompanied by severe humoral hypercalcemia. The hypercalcemia was associated with a parathyroid hormone (PTH)-like substance.

Neuroendocrine tumors of the gastrointestinal tract

Neoplastic proliferations of neuroendocrine cells (NE) may occur throughout the entire GI tract but affect particularly appendix and ileum ("midgut carcinoids"), rectum ("hindgut carcinoids"), as well as stomach and the duodenum ("foregut carcinoids"). Only more exceptionally, they arise in the esophagus, jejunum and colon. The NE tumors encompass a heterogeneous gross and microscopic structural spectrum, ranging from inconspicuous microproliferations ("mucous membrane nevi") to bulky tumor masses. Their growth patterns are usually characteristic and easily recognized. In doubtful cases their NE differentiation becomes established by a characteristic silver affinity, by the ultrastructurally observed presence of characteristic "endocrine" secretion granules, and by immunohistochemically detectable occurrence of "pan-NE markers" (neuron-specific enolase, chromogranins, and synaptophysin), biogenic amines (mainly serotonin), and neurohormonal peptides. Foregut carcinoids usually contain serotonin, gastrin, and somatostatin, midgut carcinoids often only serotonin and tachykinins, whereas the hindgut carcinoids as a rule are multihormonal with a wide spectrum of hormonal peptides, including even insulin. Most GI NE tumors are found in the appendix (50%) and the ileum (30%). Practically all (98%) of the appendiceal NE tumors are benign. They have recently been proposed as arising from apparently Schwann-cell-related NE cells in the submucosa, whereas the ileal--and probably also all the other non-appendiceal NE tumors--are derived from the totipotential cells in epithelial crypts of the mucosa. Among the ileal NE neoplasms a large number can metastasize and result in a fatal outcome. The ability to metastasize is related to the size and to the multiplicity of the primary tumors at the time of initial diagnosis and, to some extent, to their histopathologic growth pattern. Now, some relationship between the prognosis and the cytochemically assessed nuclear DNA content of the NE tumor cells has also been established; not less than about 1/4 to 1/3 seem to be aneuploid. Almost 90% of the rectal carcinoids are benign. Exceptionally, a highly malignant NE neoplasms can arise from the colon/rectum--as well as from the esophagus--composed of NE cells of small and intermediate size. The NE tumors of the stomach are often composed of ECL (enterochromaffin-cell-like) cells; such ECL cell carcinoids are related to atrophic gastritis with pernicious anemia; experimentally, they can be induced by hypergastrinemia in rats. Duodenal carcinoids often contain psammoma bodies and can be associated with neurofibromatosis.

Bronchial carcinoid tumor mimicking acinic cell tumor

A rare case of carcinoid tumor mimicking an acinic cell tumor is presented. A bicameral tumor measuring 8 x 6 mm in size was recognized in the right lung (B5bi) upon gross examination. Microscopically, the tumor consisted of basophilic polygonal cells forming an acinar pattern. Ultrastructurally, the majority of tumor cells had large membrane-bound cytoplasmic granules, measuring about 600 nm in diameter, which were similar to secretary granules of serous acinar cells (zymogen granules). These findings suggested that the tumor might be an acinic cell tumor originating from the bronchial gland. However, tumor cells were shown to be negative for periodic and Schiff (PAS) stain or lactoferrin, lysozyme and amylase immunohistochemically. On the other hand, they were shown to be argyrophilic by Grimelius stain and showed immunohistochemically positive reaction for serotonin, suggesting that the granules were neurosecretory granules and not zymogen granules. Based on these findings, we concluded that this tumor was an unusual variant of carcinoid tumor mimicking acinic cell tumor. Although carcinoid tumor has a wide histological spectrum, there has been no reported case, to our knowledge, of acinic cell tumor-like carcinoid tumor.

Squamous-cell carcinoma of the colon. Experience at the University of Chicago, review of the literature, report of two cases

Primary squamous-cell and adenosquamous-cell carcinoma of the colon are uncommon and their characteristics not well known. This paper reports the clinical features and pathologic findings of two colonic adenosquamous carcinomas and reviews other reports of adenosquamous and squamous carcinoma of the colon from the English medical literature. Including these two cases, 63 cases have been reported since 1927. Of these, six occurred in patients with ulcerative colitis, three occurred at the colonic opening of chronic colocutaneous fistulas, and concomitant schistosomiasis was present in two patients. Synchronous squamous-cell carcinoma of the colon was present in 3.2 percent of cases and 10 percent had either antecedent, synchronous, or metachronous adenocarcinoma of the colon. These lesions appeared to be distributed uniformly throughout the colon. The five-year survival after resective therapy for primary squamous-cell and adenosquamous-cell carcinoma of the colon calculated with life table analysis is 50 percent for Dukes' B lesions, 33 percent for Dukes' C lesions, and 0 percent for Dukes' D lesions.

The establishment of two rat colonic carcinomas in tissue culture. A basic prerequisite for standardized experiments on the biology of colonic carcinomas in vivo

Two rat colonic carcinomas (DMH-Co-1 and DMH-Co-2) derived from dimethyl-hydrazine-induced metastasizing adenocarcinomas were established as permanent cell lines. By means of electron microscopy, immunofluorescence microscopy and biochemical analysis of cytoskeletal components, it has been shown that both tumor cell lines retain in vitro the phenotypic characteristics of the primary tumors. The in vitro growth properties revealed only minor differences between the two cell lines. After retransplantation in vivo, DMH-Co-2 gave rise to moderately differentiated adenocarcinomas, whereas the tumors arising from DMH-Co-1 exhibited a continuum of differentiation encompassing adenocarcinomas, undifferentiated carcinomas and squamous cell carcinomas. These permanent cell lines offer the opportunity for isolating divergent subpopulations by in vitro cloning and facilitate standardized experiments on their biological behaviour in vivo.

Adenosquamous carcinoma of the colon presenting with hypercalcemia

A rare adenosquamous carcinoma of the colon occurred in a 41-year-old patient. Its presentation with hypercalcemia, in the absence of osseous metastases, has not been described previously. The hypercalcemia in this case was due to the elaboration of a parathyroid hormone-like substance by the tumor. The general characteristics of primary adenosquamous and squamous cell carcinomas of the colon are presented. These tumors present with advanced disease, in younger patients, and follow a highly aggressive course, as compared with adenocarcinomas of the colon. The cause of the malignancies, in the light of current theories regarding their genesis, is discussed.

Adenosquamous carcinoma of the stomach. Histogenetic and ultrastructural studies

Adenosquamous carcinoma of the stomach in a 45-yr-old Japanese woman was studied ultrastructurally and light microscopically. The tumor consisted of combined areas of poorly and moderately differentiated adenocarcinoma and squamous cell carcinoma, with keratinization. Noteworthy was the demonstration of individual cells containing both tonofibrils and mucous vacuoles. The frequencies of this type of tumor in early and advanced gastric carcinomas are given attention and the pathogenesis is discussed with respect to our own observations and to data in the literature.

Long term survival case of small (oat) cell carcinoma of the rectum

A long term survival case of small (oat) cell carcinoma of the rectum in a 39-year-old female is presented. She complained of anal pain and occasional anal bleeding. The tumor was located at the anterior wall in the lower rectum. Biopsy specimens revealed a carcinoid tumor. She underwent trans-anal local resection for the first time in December, 1980. Macroscopic findings of the resected specimen showed a small nodule, 0.4 by 0.4 by 0.5 cm, with yellowish cut-surface. Microscopically, the tumor deeply invaded the submucosal layer. The appearances were indistinguishable from pulmonary small (oat) cell carcinoma. Since lymphatic permeations were moderately recognized in the tumor, she underwent radical operation (Miles' operation) with lymphadenectomy. Microscopic findings of the resected rectum revealed an intramural metastatic lesion with marked lymphatic permeations in the submucosal layer 2 cm distant from the primary lesion. Up to date, there is no evidence of local recurrence or liver metastasis. Small (oat) cell carcinoma of the rectum easily metastasizes lymphogenously through the lymph system from an early stage of the development. Wide surgical resection will be needed to give a long term survival even if the tumor is extremely small.

Small cell neuroendocrine carcinoma of the colon and rectum: clinical, histologic, and ultrastructural study and immunohistochemical comparison with cloacogenic carcinoma

In an effort to provide immunocytochemical data that would be useful in distinguishing between small cell epithelial tumors of the anorectal region, 10 cases of neuroendocrine small cell colorectal carcinoma (NSCCC) and five cases of cloacogenic carcinoma (CC) were studied with antibodies to cytokeratin, epithelial membrane antigen (EMA), chromogranin, blood group isoantigens (BGI), carcinoembryonic antigen (CEA), Leu-M1, Leu-7, leukocyte common antigen (LCA), S-100 protein, neurofilaments (NF), neuron-specific enolase (NSE), serotonin, and 14 neuropeptides. The diagnoses for all 15 tumors were verified ultrastructurally. Among the antigenic determinants considered, reactivity for low- and medium-molecular-weight cytokeratin, EMA, NSE, and NF was seen in the majority of NSCCCs, whereas the CCs were positive for all cytokeratin classes, BGI, EMA, and CEA. In addition, Leu-M1, Leu-7, and chromogranin were each expressed in three cases of NSCCC. None of the other antisera yielded positive results in tumors of either type. All 10 patients with NSCCC died of their tumors within 11 months of clinical presentation, while four of the five CCs proved fatal, with an average survival of 28 months. One of the patients with CC was free of disease 31 months after diagnosis. These data suggest that an immunocytochemical panel, consisting of antibodies to high-molecular-weight cytokeratin, BGI, CEA, NSE, and NF (and possibly Leu-7 and chromogranin as well), is capable of distinguishing between NSCCC and CC in problematic cases. Although tumors of both types are aggressive, it is possible that the survival statistics for both may be improved through more accurate diagnostic classification.

The occurrence and clinicopathological significance of serotonin immunoreactive cells in large bowel carcinoma

We studied the incidence, clinicopathological relevance and prognostic significance of serotonin immunoreactive cells in a clinically well-documented series of 300 large bowel cancer patients. Serotonin immunoreactive cells were detected in 8 per cent of the carcinomas, occurring either as focal clusters (4.7 per cent) or as occasional single cells (3.3 per cent). Both types frequently displayed presence of mucin and/or immunoreactivity for secretory component as well. In respect of localization, stage or tumour extension and histological grade tumours with serotonin immunoreactivity showed no significant differences in comparison with carcinomas lacking this feature. In terms of survival, however, the tumours with serotonin immunoreactivity demonstrated a more aggressive clinical course in comparison with tumours without these cells. This phenomenon reached borderline statistical significance. It is therefore concluded that the study of serotonin immunoreactivity in large bowel carcinomas enables the identification of a subpopulation of colorectal carcinomas with a relatively poor prognosis.

Stem cell carcinoma of the colon and rectum. Report of two cases and review of the literature

Two cases of highly malignant tumors, one originating in the sigmoid colon and the other in the rectum, are presented. Both tumors showed light microscopic, electron microscopic, and immunohistochemical evidence of multidirectional differentiation. The tumors were composed mainly of undifferentiated cells, but focally merging into areas with adenocarcinomatous and squamous differentiation. Ultrastructurally and histochemically, a predominant endocrine differentiation was present in the undifferentiated areas of the tumors. These two cases lend further support to the recent concept of a pluripotential stem cell in the mucosa of the gastrointestinal tract capable of differentiation in several directions.

Small-cell carcinoma of the rectum. Clinicopathologic study

Three cases of small-cell carcinoma of the rectum are presented. Our conclusions are as follows: small-cell carcinoma and carcinoid tumor of the rectum might have a common origin; indications for surgical intervention for small-cell carcinoma of the rectum should be considered seriously; small-cell carcinoma of the rectum should be classified as an aggressive type of rectal tumor that metastasizes easily to distant organs.

Squamous metaplasia in colonic adenomata: report of two cases

Two cases of squamous metaplasia in colonic adenomata are reported. Since squamous metaplasia is known to occur rarely in the colon it is surprising that its occurrence in colonic adenomata has not been emphasized; this is more remarkable as its presence may have clinical significance as a precursor of rare forms of carcinoma of the colon.

Extrapulmonary oat cell carcinoma

Primary extrapulmonary tumors with histologic features indistinguishable from bronchogenic oat cell carcinoma are appearing with increasing frequency in the literature. These tumors have been described in the esophagus, stomach, pancreas, larynx, hypopharynx, salivary glands, nasal cavity and paranasal sinuses, thymus, small and large bowel, uterine cervix, endometrium, breast, prostate, urinary bladder, and skin. It is now widely believed that oat cell carcinoma is a poorly differentiated counterpart of carcinoid tumor and that both originate from an endocrine cell system. In this article, the authors review all cases of extrapulmonary oat cell carcinomas, which they were able to find in the English literature, and report personally studied examples of these tumors, occurring in the esophagus, stomach and urinary bladder. A closely related, if not identical, tumor arising in the skin is also described. It is emphasized that a wider recognition of these tumors is likely to lead to their more frequent diagnosis and possible treatment.

Histopathological and immunohistochemical study of neuroendocrine tumors of the rectum

A clinicopathological and immunohistochemical study was carried out on 32 cases of neuroendocrine tumors of the rectum. Typical carcinoids consisted of 27 cases, histologically showing uniform round to columnar cells forming solid alveolar nests and ribbon-like or trabecular arrangement. Neuroendocrine carcinomas consisted of 5 cases in which tumor cells with prominent nuclear atypism were arranged in a ribbon-like or trabecular fashion and formed gland-like structures. There were also small round tumor cells resembling lymphocytes. The prognosis of neuroendocrine carcinomas is very poor with marked tumor invasion of lymphatics and veins resulting in liver metastases and death within one year after operation. Thirty cases out of the 32 showed a positive argyrophil reaction, while immunohistochemistry of 29 cases revealed more than one peptide hormone in 23 cases. The most common hormone was somatostatin being present in 18 of the 23 tumors and glucagon in 16 of the 23 tumors. Gastrin/CCK and calcitonin were proven in 6 of the 23 tumors and in 4 of the 23 tumors, respectively. On the other hand, more than two hormones was present in 15 of the 23 tumors examined. Histologically, neuroendocrine tumors have a very wide spectrum. Histogenetically, typical carcinoids and neuroendocrine carcinomas are considered to be of the same origin with the former showing morphological and functional differentiation to endocrine cells and the latter being more undifferentiated.

Adenosquamous carcinoma and carcinoidal differentiation of the colon. Report of a case

A case of colonic tumor demonstrating both adenosquamous carcinomatous and carcinoidal features is reported. Previous record of such an occurrence has not been encountered. The relationship between the three elements appears to be an intimate one. It is not regarded as purely coincidental, but supports the possibility of a close histogenetic relationship between the three components.

Oat cell carcinomas of the oesophagus: a clinico-pathological study of 23 cases

A review of 955 patients with primary oesophageal carcinoma treated with this hospital revealed 23 cases of small cell anaplastic carcinoma of the oat cell type. Fifteen were females and eight were males. In each case the histological appearances were identical to those of the oat cell carcinoma which is much more commonly encountered in the lung. In none of these cases was there any evidence of a primary oat cell carcinoma outside the oesophagus. Argyrophilic granules were seen in three cases and granules of the neurosecretory type were present in five. We conclude that neither of these findings is a prerequisite for making a diagnosis of oesophageal oat cell carcinoma. The histogenesis of this tumour is reviewed and briefly discussed.

Undifferentiated carcinoma of the colon containing exocrine, neuroendocrine and squamous cells

The light microscopic, electron microscopic and histochemical features of a highly malignant colonic tumor resected from a 39 year old man are presented. The tumor was composed predominantly of undifferentiated cells with focally admixed neuroendocrine, exocrine and squamous cells, occasionally arranged in an organoid manner. Histochemically the tumor contained argyrophilic cells as well as cells that reacted positively with the antibodies to alpha-1-antitrypsin, alpha-1-antichymotrypsin, carcinoembryonic antigen and lysozyme. The term "stem cell carcinoma of the intestine" is proposed for this highly malignant tumor composed of undifferentiated cells exhibiting only focally their multidirectional developmental capacity.