Background. Merkel cell carcinoma (MCC) is a neuroendocrine tumour, with typical morphological features. Originally reported as primary carcinoma of skin, it has been described in numerous other sites such as lymph-nodes, breast and salivary glands. Cytogenetic studies have shown trisomy of chromosome 6 in about 50% of MCC of both skin and lymph nodes indicating a strict similarity of these two forms. Recent molecular studies revealed in up to 80% of cases a clonally integrated polyomavirus, named Merkel cell polyomavirus (MCPV). It seems that MCPV is restricted to MCC as no positivity was found in 74 cases of visceral neuroendocrine carcinomas [Am J Surg Pathol. 2009 Dec;33(12):1771-7]. Aim of the present study was to verify the presence of MCPV in MCC of lymph nodes and parotid to further investigate similarities and differences between the two groups. Methods. Cases of primary MCC studied were: 7 of lymph nodes, 2 of parotid, 13 of skin. 13 cases of small cell carcinoma (SCC) of lung (11 primaries and 2 brain metastases) were also analyzed. Immunohistochemistry for keratin 20, chromogranin, synaptophysin and TTF1 was obtained in all cases. Tumour cells were microdissected and DNA extracted. Viral DNA was studied with PCR assay using primers previously described by Duncavage et al. [Mod Pathol. 2009 Apr;22(4):516-21]. The PCR products were evaluated in a 3% agarose gel and sequenced. Results and conclusions. MCPV was detected in 4 cases of MCC primary of lymph node (in 3 cases DNA was not evaluable) and in all cases of parotid and cutaneous MCC. Keratin 20 was positive in all cases of MCC. On the contrary, all cases of pulmonary SCC were negative for both MCPV and CK20. It appears that cutaneous and extracutaneous MCC share similar histological, immunohistochemical and molecular features. This is a further evidence that Merkell cell origin is no longer tenable as Merkel cells have not been described in lymph nodes and parotid glands.
Polyoma virus dna integration in extracutaneous merkel cell –like carcinoma
DE BIASE, DARIO;ASIOLI, SOFIA;
2010
Abstract
Background. Merkel cell carcinoma (MCC) is a neuroendocrine tumour, with typical morphological features. Originally reported as primary carcinoma of skin, it has been described in numerous other sites such as lymph-nodes, breast and salivary glands. Cytogenetic studies have shown trisomy of chromosome 6 in about 50% of MCC of both skin and lymph nodes indicating a strict similarity of these two forms. Recent molecular studies revealed in up to 80% of cases a clonally integrated polyomavirus, named Merkel cell polyomavirus (MCPV). It seems that MCPV is restricted to MCC as no positivity was found in 74 cases of visceral neuroendocrine carcinomas [Am J Surg Pathol. 2009 Dec;33(12):1771-7]. Aim of the present study was to verify the presence of MCPV in MCC of lymph nodes and parotid to further investigate similarities and differences between the two groups. Methods. Cases of primary MCC studied were: 7 of lymph nodes, 2 of parotid, 13 of skin. 13 cases of small cell carcinoma (SCC) of lung (11 primaries and 2 brain metastases) were also analyzed. Immunohistochemistry for keratin 20, chromogranin, synaptophysin and TTF1 was obtained in all cases. Tumour cells were microdissected and DNA extracted. Viral DNA was studied with PCR assay using primers previously described by Duncavage et al. [Mod Pathol. 2009 Apr;22(4):516-21]. The PCR products were evaluated in a 3% agarose gel and sequenced. Results and conclusions. MCPV was detected in 4 cases of MCC primary of lymph node (in 3 cases DNA was not evaluable) and in all cases of parotid and cutaneous MCC. Keratin 20 was positive in all cases of MCC. On the contrary, all cases of pulmonary SCC were negative for both MCPV and CK20. It appears that cutaneous and extracutaneous MCC share similar histological, immunohistochemical and molecular features. This is a further evidence that Merkell cell origin is no longer tenable as Merkel cells have not been described in lymph nodes and parotid glands.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
