Fibroma digital celular: un tumor periungueal CD34 positivo / Cellular digital fibroma: distinctive CD34 positive tumor

RESUMEN

El fibroma digital celular consiste en una neoplasia benigna, generalmente solitaria, localizada en un dedo del pie o de la mano, que suele comprometer la región ungular y regresar espontáneamente. Presentamos un caso de sexo masculino de 27años, con una lesión nodular en el segundo dedo del pie derecho. La histopatología mostró una proliferación fuso celular dérmica acral, con presencia de fibroblastos reactivos y mastocitos, entre haces de colágeno engrosados y capilares dilatados. Inmunomarcación vimentina (+), CD68 (+) en células aisladas, proteína s100 (-), actina muscular lisa (-), CD34 (+) focal.

ABSTRACT

Digital fibromas are common benign acral tumors typically reported as angiofibromas (AFs) or acquired digital fibrokeratomas (ADFs). Cellular variants are not well recognized. Nodules develop mainly in fingers and toes. There is high recurrence but spontaneous regression without treatment has also been reported. We report a man of 27 years-old, showing a one cm nodule in the second finger of the right foot. Histological examination revealed spindled tumor cells containing characteristic intracytoplasmic inclusion bodies that stained with vimentin, CD68 positive, protein S100 negative, muscle specific actin negative and CD34 positive. These findings suggest that a subset of digital fibromas is characterized by a dense cellular proliferation of CD34 positive spindle cells. Awareness of this variant of digital fibroma and its staining pattern is critical in preventing misdiagnosis as dermatofibrosarcoma protuberans, particularly in superficial biopsies.