Plexiform Fibrohistiocytic Tumor in Three Children

Abstract

Plexiform fibrohistiocytic tumor is a very rare fibrohistiocytic tumor of intermediate malignancy. It can occur at any age but is more prevalent in children and in young adults. Here we present the clinicopathologic findings of three girls with this tumor. The patients were 8 months, 14 months, and 7 years of age. They each presented with a solitary, nontender, subcutaneous nodule or plaque. Light microscopy and immunohistochemical study findings were compatible with plexiform fibrohistiocytic tumor. We also review the previously published cases in the English-language literature.

Features of Plexiform Fibrohistiocytic Tumor in Skin Punch Biopsies: A Retrospective Study of 6 Cases

“…PFHTs occur most frequently in the upper extremities (63% of cases in the largest study) but can present on the lower extremities, buttock, trunk, and back and more rarely on the head and neck. 6,7 Our small series included lesions from the upper and lower extremities and the abdomen, back, and buttock. Clinically, the differential diagnosis included dermal and subcutaneous fibrohistiocytic lesions, as well as relatively common cystic lesions in children and young adults, such as pilomatricoma.…”

An erythematous raised dermatofibroma-like nodule

“…The most frequent site is the upper limb (about 60% of cases), followed by the lower limb (about 30%) . The clinical differential diagnoses include dermatofibroma, dermatofibrosarcoma protuberans, pilomatricoma and myofibroma …”

Plexiformer fibrohistiozytärer Tumor

“…Dank der heutzutage zur Verfü-gung stehenden Immunhistochemie und Elektronenmikroskopie konnte in neueren Studien gezeigt werden, dass es sich hier nicht um eine wirkliche histiozytäre Differenzierung handelt. Es handelt sich vielmehr um ein Gewebe, das aus Zellen besteht, die lediglich Fibroblasten und Histiozyten ähneln [1,5].…”

“…Interessant ist es, dass der PFT keine anderen positiven histiozytären Marker (z. B. HLA-DR) aufweist, sodass man eine sichere histiozytä-re Differenzierung nicht aufzeigen kann [5]. Andererseits zeigen die Spindelzellen eine Positivität für Aktin und Vimentin.…”

“…Andererseits zeigen die Spindelzellen eine Positivität für Aktin und Vimentin. Dies legt eine myofibroblastäre Differenzierung nahe [5,7].…”