[Merkel cell carcinoma of the skin in a patient with myasthenia gravis]. / Tumore di Merkel della cute in paziente con miastenia gravisi.

Merkel cell carcinoma is a rare, aggressive neuroendocrine tumor of the skin commonly seen in the elderly on the head, neck and extremities, with a predisposition for local regional and distant spreading. A case of Merkel cell carcinoma occurred in a woman treated with immunosuppressive therapy for myasthenia gravis, is described and the possibility of a link between the immunosuppressive and/or oncogenic therapy and this tumor is suggested.

Cytogenetic analysis in essential thrombocythemia at diagnosis and at transformation. A 12-year study.

Between 1979 and 1988, 86 patients with clinical and laboratory findings consistent with essential thrombocythemia (ET) were karyotyped at diagnosis. Four patients showed a Philadelphia chromosome and underwent myeloid blastic crisis 2.5-4.5 years later, strongly suggesting a diagnosis of chronic myeloid leukemia. A partial deletion of 13q was seen in another case evolving to leukemia a few months later. Five cases, with normal karyotypes at diagnosis, developed acute transformation after more than 5 years of chronic phase. Four of them showed unusual clonal karyotype abnormalities involving different chromosomal regions. The numerical abnormalities found were trisomy 22 in one case, and trisomy 8 and 19 in another, while structural changes included partial deletion of 5p, partial deletion of 6q, pericentric inversion of chromosome 12, and partial deletion of 20q. These abnormalities have not been previously reported in ET. This investigation confirms the absence of a specific cytogenetic marker for ET, and the infrequent transformation to acute leukemia, often with chromosomal clonal disorders.