An atypical chondroid syringoma with malignant degeneration: Utility of comparative genomic hybridization in confirming the diagnosis

[Cutaneous adnexal tumours: Development and synthesis of diagnostic fusion genes]

Cutaneous adnexal tumours are a heterogeneous group of epithelial lesions that includes tumours with follicular, sudoral and/or sebaceous differentiation, or even several combined lines of differentiation. Over the last few years, molecular analysis of these lesions has allowed to identify specific molecular events responsible for tumour development in an increasing number of tumour types. Like other rare neoplasms, such as soft tissue tumours, adnexal tumours display fusion genes resulting from chromosomal translocations that may be specific for the diagnosis if molecular data are properly integrated in the clinical and morphological setting. Molecular testing of adnexal tumours is valuable as it allows to strengthen the robustness of the diagnosis for a group of tumours displaying a wide morphological spectrum. It has allowed to refine the diagnostic criteria and to develop increasingly specific diagnostic immunostainings. Finally, molecular testing has been responsible for the identification of new entities or morphological subtypes of previously known entities. The aim of this review is to provide an update on cutaneous adnexal tumours associated with fusion genes and to evaluate the impact of molecular data on the diagnosis of these lesions.

Chondroid syringoma: an unusual presentation in a 7-year-old boy

Coined in 1961 by Hirsch and Helwig, the term chondroid syringoma refers to a rare mixed tumour of subcutaneous tissue. Histologically, these tumours are almost identical to pleomorphic adenomas, arising from salivary glands. With the obvious difference being the presence of sweat gland tissue (syringoma) within a matrix of cartilage (chondroid). These mixed tumours remain scarce throughout the world, with an incidence of less than 0.098%. The vast majority of cases are reported in middle-aged and older adults, where they typically present as painless swellings in the head and neck, which gradually grow in size.