PubMed · 7632011
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A Gaudillère, L Misery. 1994. [Merkel cell].. https://pubmed.ncbi.nlm.nih.gov/7632011/
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PURPOSE: Merkel cell carcinoma (MCC), being a small cell carcinoma, would be expected to be sensitive to radiation. Clinical analysis of patients at our center, especially those with macroscopic disease, would suggest the response is quite variable. We have recently established a number of MCC cell lines from patients prior to radiotherapy, and for the first time are in a position to determine their sensitivity under controlled conditions. METHODS AND MATERIALS: Some of the MCC lines grew as suspension cultures and could not be single cell cloned; therefore, it was not possible to use clonogenic survival for all cell lines. A tetrazolium based (MTT) assay was used for these lines, to estimate cell growth after gamma irradiation. Control experiments were conducted on lymphoblastoid cell lines (LCL) and the adherent MCC line, MCC13, to demonstrate that the two assays were comparable under the conditions used. RESULTS: We have examined cell lines from MCC, small cell lung cancer (SCLC), malignant melanomas, Epstein Barr virus (EBV) transformed lymphocytes (LCL), and skin fibroblasts for their sensitivity to gamma irradiation using both clonogenic cell survival and MTT assays. The results show that the tumor cell lines have a range of sensitivities, with melanoma being more resistant (surviving fraction at 2 Gy (SF2) 0.57 and 0.56) than the small cell carcinoma lines, MCC (SF2 range 0.21-0.45, mean SF2 0.30, n = 8) and SCLC (SF2 0.31). Fibroblasts were the most sensitive (SF2 0.13-0.20, mean 0.16, n = 5). The MTT assay, when compared to clonogenic assay for the MCC13 adherent line and the LCL, gave comparable results under the conditions used. CONCLUSION: Both assays gave a range of SF2 values for the MCC cell lines, suggesting that these cancers would give a heterogeneous response in vivo. The results with the two derivative clones of MCC14 (SF2 for MCC14/1 0.38, MCC14/2 0.45) would further suggest that some of them may develop resistance during clonogenic evolution.
Merkel cell carcinoma of the genitalia is very rare and to date has been found only in vulvar mucosa. We describe an aggressive Merkel cell tumor in the frenulum of the penis with lymph node metastases, local recurrence, and eventually widespread dissemination. The primary tumor was associated with discontiguous squamous cell carcinoma in situ. This is the first report of Merkel cell (neuroendocrine) carcinoma in this anatomic site.
BACKGROUND: Merkel cell carcinoma is an uncommon malignancy of the skin that often portends a poor prognosis. Since its first description by Toker in 1972, a plethora of case reports and articles regarding the etiopathogenesis and treatment have been published spanning multiple medical and surgical disciplines. Much confusion still exists regarding the diagnosis and treatment of this ominous tumor. OBJECT: Through extensive review of the medical, surgical, and pathological literature, to collate the observations of multiple investigators and summarize these findings. METHODS: Articles from journals of multiple subspecialties were carefully reviewed with particular emphasis placed on epidemiology, prognosis, histology, immunohistochemistry, electron microscopy, tumor origin, treatment, and work-up of Merkel cell carcinoma. RESULTS: Merkel cell carcinoma is an aggressive malignant neoplasm. Local recurrence develops in 26-44% of patients despite therapy. Up to three-fourths of patients eventually develop regional nodal metastases with distant metastases occurring in one-third of all patients. Reported overall 5-year survival rates range from 30% to 64%. CONCLUSION: Treatment recommendations unfortunately are based more on anecdotal than scientific data because of the rarity of the tumor and its recognized high risk. Most authors recommend wide local excision of the primary lesion and regional lymph node resection if lymph nodes are palpable followed by x-irradiation of both the postsurgical bed and lymph node basin. The role of elective lymph node resection in the absence of clinically positive nodes remains controversial.