Small Cell Neuroendocrine Carcinoma With Skeletal Muscle Differentiation
Memorial Sloan-Kettering Cancer Center, New York, New York, United States American Journal of Surgical Pathology
(Impact Factor: 5.15).
03/2000; 24(2):223-30. DOI: 10.1097/00000478-200002000-00008
Three cases of neuroendocrine carcinoma showing skeletal muscle differentiation are presented. The tumors were located in the skin and subcutaneous tissue, the urinary bladder, and the nasal cavity respectively, and were composed by two cell types admixed intimately with each other. One cell type had features identical to those seen in conventional small cell neuroendocrine carcinoma, including scanty cytoplasm, round nuclei with fine granular chromatin, immunohistochemical reactivity for neuron-specific enolase, chromogranin and cytokeratins, and electron-dense granules on ultrastructural examination. The second cell type was either plasmacytoid or elongated and straplike, with abundant eosinophilic cytoplasm and irregular nuclei with prominent nucleoli. These cells showed immunohistochemical positivity for desmin, sarcomeric actin, myoglobin, and myogenin. They also exhibited ultrastructural evidence of rhabdomyoblastic differentiation in the form of contractile filaments with abortive Z-band formation. An origin from a cell capable of dual differentiation toward neuroendocrine and rhabdomyoblastic elements is postulated for these tumors.
Available from: Satoru Munakata
- "As in our case, neuroendocrine carcinomas are rarely combined with sarcomas with skeletal muscle differentiation. To date, only 10 such cases have been reported [8–10]. These tumors originate from various anatomical sites, including the skin, nasal cavity, larynx, lung, small intestine, anorectal region, pancreas, and urinary bladder. "
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ABSTRACT: Malignant Müllerian mixed tumors (MMMTs) of the uterine cervix are extremely rare, accounting for 0.005% of all cervical malignancies. To date, only approximately 50 well-documented cases have been reported. Although several epithelial components have been described in cervical MMMTs, small cell neuroendocrine carcinoma (SCC) has not appeared in the English literature. We present a 43-year-old woman, para 2 gravida 2, who had MMMT with SCC and rhabdomyosarcoma components in the uterine cervix. She was referred to our hospital because of a cervical mass with an abnormal Pap smear result. Cervical biopsy revealed SCC. After neoadjuvant chemotherapy with balloon-occluded arterial infusion, she underwent type II radical hysterectomy with pelvic lymphadenectomy. Histological analysis revealed that the cervical tumor comprised SCC and rhabdomyosarcoma components. Genotype analysis indicated human papillomavirus type 18. She underwent concurrent chemoradiation therapy. The patient had been free of the disease and showed no evidence of recurrence 38 months after operation.
Available from: PubMed Central
- "Finally, the observed heterogeneity in MCC rather favors less differentiated cells as cells of origin . In detail, MCCs associated with diverse differentiation patterns have been described: squamous , squamous and sarcomatous , melanocytic , eccrine , leiomyosarcomatous , rhabdomyoblastic , and fibrosarcomatous  differentiation. Although there is a certain immunophenotypical diversity in MCs themselves , the multitude of differentiation patterns in MCC rather points to stem or early progenitor cells as cells-of-origin. "
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ABSTRACT: Merkel cell carcinoma (MCC), a highly aggressive skin tumour with increasing incidence, is associated with the newly discovered Merkel cell polyomavirus (MCPyV). Studies on MCC and MCPyV as well as other risk factors have significantly increased our knowledge of MCC pathogenesis, but the cells of origin, which could be important targets in future therapies, are still unknown. Merkel cells (MCs), the neuroendocrine cells of the skin, were believed to be at the origin of MCC due to their phenotypic similarities. However, for several reasons, for example, heterogeneous differentiation of MCCs and postmitotic character of MCs, it is not very likely that MCC develops from differentiated MCs. Skin stem cells, probably from the epidermal lineage, are more likely to be cells of origin in MCC. Future studies will have to address these questions more directly in order to identify the physiological cells which are transformed to MCC cells.
Available from: Maria Pia Foschini
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ABSTRACT: In the skin, endocrine tumors showing areas with nonendocrine features and nonendocrine tumors showing endocrine differentiation are present. (1) Neuroendocrine carcinomas with nonendocrine differentiation: Merkel cell carcinoma (MCC) of the skin has been frequently described in association with squamous cells carcinoma (SCC) which can arise separately (as synchronous or metachronous lesions) from MCC as well as closely intermixed. In the first event the possibility that the lesions are sustained by same causative factors (among which sun exposure is the most probable) is suggested. In cases of lesions closely intermixed the possibility of an origin from a common precursor is suggested. Furthermore, cases of MCC have been described to contain glandular, melanocytic, striated muscle, and lymphoepithelioma-like features. These latter findings further support the hypothesis of tumors showing divergent differentiations. (2) Nonendocrine tumors showing endocrine differentiation: Basal cell carcinoma (BCC) was the first cutaneous nonendocrine tumor described to contain neuroendocrine granules. Presence of endocrine features were subsequently confirmed with immunohistochemical studies. Endocrine features were then described in sweat gland apocrine and eccrine carcinomas. Endocrine elements present in BCC and in sweat gland carcinomas do not show morphological and immunohistochemical features of Merkel cells. Thus the possibility that these tumors develop an immature Merkel cell or a new type of endocrine cell of the skin is suggested. Tumors with follicular differentiation such as trichoblastomas and trichofolliculomas contain a high number of Merkel cells. As Merkel cells are numerous in hair follicles of human fetal skin, the possibility that these tumors recapitulate the human skin embryogenesis is suggested.
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