Characteristic Clinical and Dermoscopic Features of Nonvolar Poroma.

BACKGROUND: A poroma typically presents as a solitary, pink-to-red papule or nodule in acral volar areas. However, in nonvolar areas, this typical clinical feature (TCF) can be difficult to identify. OBJECTIVE: We aimed to compare clinical and dermoscopic characteristics between nonvolar poroma (NVP) and volar (ie, typical) poroma (VP). METHODS: We assessed the clinical and dermoscopic characteristics of 40 patients with poromas who were divided into the NVP and VP groups. RESULTS: Of the 40 patients, 20 (50.0%) were allocated to the NVP group and 20 (50.0%) to the VP group. Pigmented variants were more common in the NVP group than in the VP group (60.0% vs 5.0%). The TCF of poroma was observed less frequently in the NVP than the VP group (45.0% vs 85.0%). Approximately one-third (30.0%) of patients with NVP received an initial clinical diagnosis of skin cancer. Dermoscopic patterns associated with melanoma or basal cell carcinoma were more common in the NVP group than in the VP group (65% vs 30%). CONCLUSIONS: Skin cancer-associated clinicodermoscopic features were more frequently observed in patients with NVP, who simultaneously lost dermoscopic patterns associated to poromas and acquired those associated with skin cancer, than those with VP.

Imagen ecográfica del hidroadenoma poroide / Ultrasound Image of Poroid Hidradenoma

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[Apocrine poroma. A relatively little known skin tumor with multilineage differentiation]. / Das apokrine Porom. Ein wenig bekannter Hauttumor mit adnexieller Mischdifferenzierung.

Poromas were originally classified as eccrine tumors which predominantly consist of poroid ductal cells and differentiate in the direction of sweat gland ducts. However, there have now been many reports on poromas with additional differential characteristics differentiating in the direction of sebaceous and/or apocrine glands and/or hair follicles. These tumors have been termed apocrine poromas. Multilineage differentiation within a poroma can be explained by the embryological association of the sweat duct with the so-called folliculo-sebaceous-apocrine unit. The clinical and histopathological features of apocrine poromas are reviewed in comparison to classical eccrine poromas by taking into account seven own cases of apocrine poroma and a review of the literature. It is important for histopathologists not to confuse apocrine poroma with other tumors with multilineage differentiation. Apocrine poroma needs to be distinguished from sebaceoma and from basal cell carcinoma with sebaceous differentiation, in particular, because these tumors have therapeutic consequences for the patient. The main histopathological differences between apocrine poroma, sebaceoma and basal cell carcinoma with sebaceous differentiation are explained.