Abstract
BackgroundCollision tumors are rare entities that consist of two histologically distinct tumor types arising in the same anatomic site. An association between chronic lymphocytic leukemia (CLL) and malignant melanoma (MM) has been already described. Up to now, they have been documented only at positive regional lymph nodes while we focused on collision tumor in a skin lesion.Case presentationWe characterized the genomic profile of a skin CLL/MM collision tumor in a patient with a 9-years story of CLL. Typical high-grade genomic biomarkers featured the CLL: the immunoglobulin heavy variable genes were unmutated; a clonal del(11q), involving ATM and BIRC3, was present in the peripheral blood (PB) and skin lesion, while a subclonal large del(13q)/D13S319-RB1 was detected only in the PB. Interestingly, the del(13q) clone, increased from 10% to 46% from diagnosis to relapse. NOTCH1, SF3B1, and TP53 were wild type. The MM lesion carried a BRAFV600E and a TERT promoter mutation.As the family story was consistent with a genetic predisposition to cancer, we performed mutational analysis of genes involved in familial melanoma and CLL, and of BRCA1 and BRCA2. No germinal mutation known to predispose to CLL, MM, or breast cancer was found. Interestingly, conventional cytogenetic detected a constitutional t(12;17)(p13;p13).ConclusionsOur data are consistent with distinct genetic landscape of the two tumors which were characterized by specific disease-related abnormalities. CLL cells carried poor prognostic imbalances, i.e. large deletions of the long arm of chromosomes 11 and 13, while in MM cells two functionally linked mutations, i.e. BRAFV600E and a TERT promoter occurred. Although, known germline variations predisposing to MM and/or CLL were ruled out, genetic counseling suggested the proband family was at high risk for MM.
Highlights
Collision tumors are rare entities that consist of two histologically distinct tumor types arising in the same anatomic site
Known germline variations predisposing to MM and/or chronic lymphocytic leukemia (CLL) were ruled out, genetic counseling suggested the proband family was at high risk for MM
We report the molecular-cytogenetic characterization of a unique case of CLL and MM collision tumors
Summary
Collision tumors are rare entities that consist of two histologically distinct tumor types arising in the same anatomic site. An association between chronic lymphocytic leukemia (CLL) and malignant melanoma (MM) has been already described. Up to now, they have been documented only at positive regional lymph nodes while we focused on collision tumor in a skin lesion. As the family story was consistent with a genetic predisposition to cancer, we performed mutational analysis of genes involved in familial melanoma and CLL, and of BRCA1 and BRCA2. We report the molecular-cytogenetic characterization of a unique case of CLL and MM collision tumors. Our molecular findings are consistent with an independent origin of the two tumors and suggest that both a familial predisposition and the CLL-associated immune dysregulation might have played a role in their onset
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