Clear cell carcinoid tumour of the stomach

Clear cell carcinoid of the appendix: Report of two cases with literature review

The clear cell/lipid-rich change has been described in neuroendocine tumors in several organs, but rarely observed in the appendix. In this study, we describe the morphologic, immunohistochemical features of incidentally discovered appendiceal carcinoids entirely represented by clear cells in a 22-year-old man and a 52-year-old woman. Ultrastructual examination demonstrated abundant lipid droplets and dense core granules. The mechanism leading to lipid accumulation in the cytoplasm has not been discovered, but degenerative processes following recurrent inflammatory change might be considered. This uncommon variant of appendiceal classic carcinoid tumors may bear a superficial resemblance to goblet carcinoid and/or appendiceal metastases from clear cell carcinoma. Awareness of clear cell carcinoid of the appendix will prevent incorrect diagnosis and unnecessary aggressive management.

Lipid-rich ("clear cell") neuroendocrine tumors of the pancreas in MEN I patients

The presence of "clear" or lipid-rich cells within pancreatic neuroendocrine tumors is thought to be pathognomonic of von Hippel-Lindau (VHL) disease, especially in the context of multiple tumors. However, we encountered the presence of lipid-rich cells in six of 16 patients (eight microadenomas/adenomas) who had multiple endocrine neoplasia type I (MEN I). Three of the lesions (two microadenomas and one adenoma) were composed entirely of lipid-rich cells while the remaining five lesions had a component of lipid-rich cells. All lesions containing lipid-rich cells were negative for α-inhibin, but positive for chromogranin and synaptophysin. In addition, four of the eight lesions were glucagon positive. None of the patients had clinical symptoms related to hormone production. We suggest that lipid-rich cells are not reflexly indicative of VHL, and that they may be encountered in a proportion of cases of MEN I either focally or constituting the entire neuroendocrine lesion.

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

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

Lipid-rich variant of appendiceal well-differentiated endocrine tumor (carcinoid)

Well-differentiated endocrine tumors (WDETs) of the appendix show characteristic morphologic features, including proliferation of cells with finely granulated eosinophilic cytoplasm. However, clear cell WDETs, which can present a diagnostic challenge, have been occasionally described, but it is unknown whether they represent a morphologic variant with distinct clinicopathologic features. Moreover, the clear cell appearance of the cytoplasm has never been explained. We studied 13 appendiceal WDETs composed of clear cells, which showed an immunophenotype identical to that of conventional appendiceal WDETs. Ultrastructural examination demonstrated abundant lipid accumulation. Patient survival was excellent and equal to that of conventional appendiceal WDETs. These neoplasms, which represent a lipid-rich variant of appendiceal WDETs, do not have different relevant clinical implications compared with conventional WDETs, but it is important to know of their existence for the differential diagnosis with more aggressive neoplasms, including goblet cell carcinoids and appendiceal metastases from clear cell carcinomas.

Lipid-rich and clear cell neuroendocrine tumors ("carcinoids") of the appendix: potential confusion with goblet cell carcinoid

The so-called clear cell change has been described in neuroendocrine tumors at several locations. Those associated with von Hippel Lindau disease are pathognomonically "clear" and the cytoplasmic appearance has been ascribed to intracytoplasmic lipid. However, lipid has not been demonstrated in all cases of clear cell carcinoid tumors. Such variants have not been described in carcinoid tumors of the appendix and cases with a prominent proportion of clear or more correctly, lipid-rich cytoplasm may bear a superficial resemblance to goblet cell carcinoid and/or signet ring adenocarcinoma. Seven cases, in 5 females and 2 males ranging in age from 22 to 65 years, were noted to have a population of lipid-rich and vacuolated clear cells accounting for 25% or more of the tumor population. The carcinoid tumors were incidental in all cases with 4 of patients presenting with appendicitis, 2 with concomitant mucinous cystadenocarcinomas of the appendix and 1 with an adenocarcinoma of the ascending colon. Morphologically, the tumors had a nested and trabecular pattern and were composed of an admixture of microvesicular and clear lipid-rich cells. There were no mitoses, areas of necrosis of lymphovascular invasion and all cases extended to the mesoappendix. All cases were positive for synaptophysin, chromogranin, and serotonin but negative for inhibin. Three cases were examined ultrastructurally, and showed the presence of intracytoplasmic lipid and neurosecretory granules. None of the patients have shown evidence of recurrent disease. The importance of recognizing this variant of carcinoid tumor in the appendix is to avoid confusion with goblet cell carcinoid tumors with or without a signet ring adenocarcinoma. The presence of multi-vacuolated, foamy and clear cells, some resembling signet ring or goblet cells, in otherwise classic carcinoid tumors is rare but should be considered in this context in the appendix.

Clear cell (glycogen rich) gastric adenocarcinoma: a distinct tubulo-papillary variant with a predilection for the cardia/gastro-oesophageal region

AIMS

To explore the clinicopathological and immunohistochemical profile of clear cell gastric cancers with a tubulo-papillary pattern.

METHODS

Twelve cases of clear cell gastric cancer (containing a minimum of 10% of clear cells) were studied. The cases were stained with: CK7, CK20, CEA, AFP, cyclin D1, E-cadherin and CDX-2.

RESULTS

There were nine males and three females with an age range of 62 to 82 years (mean 71.4 years). Ten cases were located in the gastric cardia with extension into the gastro-oesophageal junction and two were in the pylorus/pre-pyloric area. Tumours ranged from 2 to 9 cm (mean 4.5 cm), nine were polypoid, exophytic grossly and all had a tubulo-papillary histological pattern. Five cases contained intracytoplasmic hyaline globules. Lymph node involvement was present in eight cases. Eight cases were CK7 positive, four were CK20 positive and all 12 were CEA, cyclin D1, E-cadherin and CDX-2 positive. All cases were AFP negative. Five patients had recurrence and/or metastasis within 6 months.

CONCLUSION

Clear cell gastric cancers have a predilection for the gastro-oesophageal junction, are polypoid, have a tubulopapillary pattern, and show over-expression of cyclin D1 but normal E-cadherin.

Endocrine tumours of the gastrointestinal tract-selected topics

This review provides an update on the pathogenesis and histopathological diagnosis of endocrine tumours of the gastrointestinal tract, concentrating on three different varieties whose careful assessment by pathologists is of particular clinical significance. These are the four types of enterochromaffin-like cell tumour of the gastric corpus, the periampullary somatostatin-containing D-cell tumour of the duodenum, and the frequently chromogranin A-negative L-cell tumour of the appendix and large intestine. In addition, the value of pathological factors in predicting the behaviour of gastrointestinal endocrine tumours and selecting therapy is discussed, and the crucial role of the pathologist in the multidisciplinary team management of these neoplasms is emphasized.

Mesothelioma with clear cell features: an ultrastructural and immunohistochemical study of 20 cases

Mesotheliomas with clear cell morphology are rare and only a few individual case reports have been documented in the literature. The author reports a series of 20 epithelioid mesotheliomas with clear features, 17 of which originated in the pleura and 3 in the peritoneum. Eighteen of the patients were men and 2 were women. Twelve patients had a history of asbestos exposure. Electron microscopy and special histochemical stains demonstrated that the cytoplasmic clearing seen in hematoxylin and eosin-stained sections resulted from multiple factors that can occur either singly or in combination. The most frequent cause of the cytoplasmic clearing was the accumulation of large amounts of intracytoplasmic glycogen. Another but somewhat less common factor was the accumulation of large amounts of lipid, which occurred alone or with glycogen. Other less common causes were marked mitochondrial swelling, the presence of numerous intracytoplasmic vesicles, and a large number of intracytoplasmic lumens. The value of immunohistochemistry in helping to distinguish epithelioid mesotheliomas from some carcinomas with clear cell morphology is emphasized. In addition, it was determined that because electron microscopy was decisive in establishing the cause of the cytoplasmic clearing in most of the cases, tissue for electron microscopy should routinely be procured for ultrastructural studies.

Clear cell (glycogen-rich) gastric adenocarcinoma

Clear cells have been described in many tumors of varying differentiation. Although clear cell carcinoma is well-recognized in the lower urinary and female genital tracts, its occurrence in the gastrointestinal tract and related structures is uncommon. There have been only a few case reports and small series reporting this morphologic phenomenon in the stomach, colon, and biliary tract. Clear cell carcinoma of the endometrium has been associated with poor prognosis, but the prognostic significance of clear cells in gastric adenocarcinoma is unknown. Herein we describe three cases of clear cell, glycogen-rich, gastric adenocarcinoma and evaluate the frequently used classification systems for gastric cancer. Two tumors showed a tubulopapillary pattern and one showed a predominantly diffuse sheet-like growth. The proliferation (MIB) index in all cases was approximately 20%. Only case 1 showed focal staining for alpha-fetoprotein and both cases 1 and 2 showed focal carcinoembryonic antigen reactivity. In conclusion, we describe three cases of clear cell gastric carcinoma that presented as high-stage disease.

Clear cell carcinoid tumor of the gallbladder. A case without von Hippel-Lindau disease

A golden yellow polyp was detected in the gallbladder of a 64-year-old man who presented with epigastric pain. The lesion was composed of clear polygonal cells arranged in a trabecular and glandular pattern. The tumor invaded through the wall into the perimuscular subserosal layer. Immunohistochemical stains showed that neoplastic cells were positive for chromogranin A, synaptophysin, somatostatin, gastrin, and pancreatic polypeptide and negative for glucagon, serotonin, insulin, S100 protein, and inhibin. This tumor resembles the recently described clear cell endocrine tumors of the gallbladder and pancreas that are associated with von Hippel-Lindau disease. Our patient, however, had neither personal nor family history indicative of von Hippel-Lindau disease. Furthermore, published accounts of clear cell endocrine tumors in von Hippel-Lindau disease describe immunoreactivity for inhibin; the current case was negative for the disease. There may be a subtype of clear cell carcinoid tumor not associated with von Hippel-Lindau disease, which is characterized by its lack of immunoreactivity against inhibin.

Malgun (clear) cell change in Helicobacter pylori gastritis reflects epithelial genomic damage and repair

Cancers may develop in the background of genomic instability with accumulated mutations. Helicobacter pylori gastritis is characterized by acute foveolitis of the proliferative zone, which is found in any stage of the gastritis as long as the infection persists. Because acute foveolitis targets specifically the proliferative zone of pits, the proliferating epithelial cells are under severe and persistent mutagenic pressure. In H. pylori gastritis, a characteristic morphological change of epithelial cells, the malgun (clear) cell change is frequently present in association with acute foveolitis. Malgun cells have enlarged euchromatic nuclei and abundant cytoplasm. The expression of proliferating cell nuclear antigen and cytokeratin 8 are typically up-regulated in them indicating that they are mitotically and metabolically active. Here, we report evidence for DNA damage and repair in malgun cells. Significant double-strand DNA breaks were shown by the consistent terminal dUTP nick-end labeling in the nuclei of malgun cells. Proteins related to DNA damage and repair, such as Ku, poly(ADP-ribosyl) polymerase, OGG1, and MSH2 were selectively up-regulated in malgun cells. Inducible nitric oxide synthase was also up-regulated. There were occasional bcl2- and p53-expressing cells suggesting that further steps of carcinogenesis took place at the single cell level. Our results suggest that the malgun cell change represents a characteristic morphological sign of cellular genomic damage and repair, and may be implicated in an early stage of carcinogenesis. It is suggested that acute foveolitis of the proliferative zone is a major pathogenetic step of gastric carcinogenesis in H. pylori gastritis.

"Malgun" (clear) cell change of gastric epithelium in chronic Helicobacter pylori gastritis

To characterize the Helicobacter pylori gastritis-associated epithelial change, we analyzed 251 randomly selected gastric biopsies. The "malgun" (clear) cell change of the gastric epithelium was noted in 229 biopsies (91.2%). Malgun cells were characterized by large, pale nuclei with a euchromatin pattern, enlarged nucleoli, and clear cytoplasm. In the proliferative zone, individual malgun cells and small clusters were often in close contact with infiltrating neutrophils, suggesting that they had developed individually in the background of acute foveolitis. Mitotic figures of malgun cells were not infrequent, including atypical ones. In the surface epithelium, most malgun cells were in clusters that were often large enough to occupy wide epithelial segments. With Warthin-Starry triple staining, they were distinguished by the absence of silver impregnation, while other cells showed staining of the heterochromatin. They displayed prominent immunostaining for low molecular weight cytokeratin (No. 8). Most malgun cells were PCNA-positive in both surface and proliferative zones, whereas Ki67-positive cells were found only in the proliferative zone. It was suggested that a population of malgun cells, which were positive for PCNA only, were in the process of active DNA repair. The malgun cell change may represent a "cellular pattern of activation" in a population which had significant DNA damage, but somehow escaped the detection by the apoptosis system. The notion of "damage at the genetic level" was supported by the observation that these cells remained at least for 8 weeks after eradication of the H. pylori infection.

Molecular identification of metastatic cancer to the skin using laser capture microdissection: a case report

BACKGROUND

In the current study the authors report a 57-year-old woman with a scalp tumor and cervical lymphadenopathy who had a previously resected duodenal carcinoid. Histologic and immunophenotypic characteristics of the duodenal carcinoid differed from those of the scalp and cervical lymph node tumors, prompting the use of molecular methodologies to make the diagnosis.

METHODS

Paraffin embedded tissues from the duodenal carcinoid, scalp, and lymph node tumors were dissected using microscopic visualization and laser capture microdissection. DNA was extracted and polymerase chain reaction (PCR) was performed to evaluate loss of heterozygosity and microsatellite alterations using primers flanking 22 polymorphic microsatellite markers from 9 chromosomal regions, including genes associated with MEN-1 (11q), CDKN2 (9p), p53 (17p), and bronchial carcinoid (3p). Microdissected lymphocytes from the three tissues were used as source of constitutional DNA (controls).

RESULTS

Fourteen of the 22 markers were informative (heterozygous in control lymphocytes). A marker on 3p12 showed loss of the same parental allele in the three tumors. A different marker on 3p14.2 showed an identical shifted band in the three tumors indicative of a common microsatellite alteration.

CONCLUSIONS

The shared molecular abnormalities among the three tumors indicated a common clonal origin, leading to a diagnosis of primary duodenal carcinoid with clear cell metastases to the scalp and cervical lymph nodes. These findings led to radiation therapy and immunotherapy rather than chemotherapy. This case illustrates the novel application of laser capture microdissection combined with PCR-based analyses of genomic markers for the identification of the origin of metastatic disease.

Pulmonary clear cell carcinoid tumor: another entity in the differential diagnosis of pulmonary clear cell neoplasia

A clear cell variant of primary pulmonary carcinoid tumor is described. The tumor arose in a 53-year-old woman who was incidentally found to have a solitary pulmonary nodule in the left upper lobe during routine chest roentgenography. Histologically, the tumor was composed of predominantly clear to lightly eosinophilic, polygonal cells with bland nuclei arranged in sheets and nests. Nuclear pleomorphism, necrosis, vascular invasion, and mitotic figures were not seen. The tumor cells were negative for oil-red-O and periodic acid-Schiff stains with and without diastase pretreatment on frozen and formalin-fixed sections, respectively. During immunohistochemical evaluation, the tumor cells were focally positive for cytokeratin and diffusely positive for neuron-specific enolase and chromogranin. Electron microscopy performed on paraffin block-retrieved tissue showed the presence of electron-dense, neurosecretory-type granules and variably sized vacuolated areas within the cytoplasm. the nature of which remained unclear. Intracytoplasmic glycogen or lipid were not identified. To our knowledge, this is the first report of pulmonary clear cell carcinoid tumor.

Clear-cell carcinoma: an ultrastructural study of 57 tumors from various sites

Clear-cell carcinoma is a convenient and frequently used descriptive term for a malignant epithelial neoplasm that is entirely or largely composed of cells with optically clear cytoplasm in hematoxylin-eosin-stained sections. Transmission electron microscopy was performed on 57 tumors from various sites to investigate the fine structural basis for the clarity of the cytoplasm. The clear appearance resulted from the presence of one or several of the following features, as the sole or predominant cause or in combination: glycogen, lipid droplets, mucin vacuoles or diffuse mucosubstances, dilated cisternae, swollen or unusually large mitochondria, large solitary membrane-limited vacuoles or numerous smaller vacuoles, intracytoplasmic lumens, expanded intercellular spaces, cytoplasmic pseudoinclusions, and a paucity of organelles. Degenerative changes contributed to the clear appearance by inducing swelling of mitochondria and creating lucent cytosol. The factors responsible for the clear cytoplasm were not always consistent with regard to tumor type or site of origin, but glycogen was the commonest reason among the 57 tumors studied and the principal cause in tumors of the female genital tract, skin, and salivary glands, while renal cell carcinomas tended to possess an admixture of glycogen and lipid droplets. Because of the heterogeneity of the subcellular changes that can produce optically clear cytoplasm, electron microscopy has a limited role in determining the primary site of a metastatic clear-cell carcinoma.

Clear cell mesothelioma

A clear cell form of epithelial mesothelioma is described. This variant does not appear to have been previously described, and it merits recognition since it is readily confused by routine light microscopy with other tumors that involve the pleura, including metastatic carcinomas composed predominantly of cells with optically clear cytoplasm. Ultrastructural and immunohistochemical studies were helpful in reaching the diagnosis in this case, and electron microscopy is particularly recommended to investigate the differential diagnosis of unusual pleural tumors.