Sporadic multiple primary melanoma cases: CDKN2A germline mutations with a founder effect.

Multiple primary cancers are one of the hallmarks of inherited predisposition. Outside the familial context, multiple primary tumors could be related either to germline de novo mutations or to low-penetrance mutations, in predisposing genes. We selected 100 patients who displayed multiple primary melanoma (MPM) without any known melanoma cases recorded within their families and looked for germline mutations in the two melanoma-predisposing genes identified to date, CDKN2A and CDK4 exon 2. Nine patients (9%) had germline mutations in CDKN2A, whereas none carried germline mutations in exon 2 of CDK4. Seven cases displayed a recurrent missense mutation, G101W, already described in more than 20 melanoma-prone families; one case carried a missense mutation never reported to date (P114S), and the last case was a carrier of a 6 bp insertion at nucleotide 57 resulting in a duplication of codons 18 and 19. To ascertain whether the G101W was a mutational hot spot for de novo mutations or a common founder mutation, we genotyped eight microsatellite markers flanking the CDKN2A gene. After allowing for recombination over time, haplotype sharing provided evidence for an original G101W mutation common to 6 out of 7 sporadic MPM cases. Therefore, it can be concluded that de novo germline CDKN2A mutations associated with MPM are rare.

[Primary cutaneous leiomyosarcoma: 32 cases]. / Léiomyosarcomes cutanés primitifs: 32 cas.

BACKGROUND: Superficial leiomyosarcomas are rare tumors, which may be confined to the dermis or extend to subcutaneous tissues. PATIENTS AND METHODS: We report the results of a retrospective study of 32 patients treated for leiomyosarcomas through a twenty-two year period (from 1975 to 1997). RESULTS: Mean age was 45 years, with 50 p. 100 of patients less than 35 years of age. Forty seven percent of the tumors were located on the lower limbs and mean diameter was 2.8 cm. Three clinical types have been isolated: nodule beneath normal epidermis (50 p. 100), purple nodule ulcerated or not (28 p. 100), swelling tumor (22 p. 100). Sixteen percent were intradermal, whereas sixty nine percent involved subcutaneous tissues. With regard to tumor grade, 37 p. 100 of tumors were grade I, 44 p. 100 of tumors were grade II, and 19 p. 100 were grade III. Immunohistochemical staining showed positive reactions for all tumors with anti-vimentin and anti-alpha smooth muscle actin. Main treatment was complete surgical excision. Follow-up informations were available for all patients and 75 p. 100 of them had a follow up period longer than a year. Five patients with leiomyosarcomas involving the subcutis developed local recurrences, and two of them died of the disease. DISCUSSION: Leiomyosarcomas can occur at any age without predominant sex-ratio. Main prognostic factors are tumor size, distal location, depth of tumor invasion and pathological grade. Immunohistological staining with anti-alpha smooth muscle actin is more sensitive and specific than with anti-desmin or anti-HHF 35. Main treatment is surgical excision with wide margins.