A case of cutaneous inflammatory myofibroblastic tumor

Abstract

Pseudo-inflammatory tumors are also known as plasma cell granuloma, inflammatory pseudo-tumor and inflammatory myofibroblastic tumor, and these tumors are a group of highly variable proliferations of myofibroblastic cells that are associated with a prominent inflammatory infiltrate. This tumor is known to most commonly occur in the lungs, bladder and gastrointestinal system with only a few cases having been reported in the skin. A previously healthy 26-year-old man presented with a 6-year history of an intermittently pruritic lesion on his back. On the histologic examination, there were spindle cells in fascicles and a mixed inflammatory cellular infiltrate of plasma cells and lymphocytes. A diagnosis of inflammatory fibroblastic tumor was made and the nodule was surgically removed. We report here on an additional case of this rare cutaneous entity, and it is probably the first such report from Korea.

Keywords: Myofibroblastic; Pseudo-inflammatory.

Fig. 1

A brownish colored palpable indurated nodule with a rough surface on the upper back.

Fig. 2

The tumor cells had plump spindle-shaped cytoplasm and the cells were arranged in fascicles or epithelioid nests with collagenous stroma (A: H&E, ×40, B: H&E, ×100). The inflammatory part showed a cellular infiltration that consisted of plasma cells and lymphocytes (C: H&E, ×100, D: H&E, ×200).

Fig. 3

(A) Staining for smooth muscle actin (SMA) highlights the spindle cells and confirms their myofibroblastic nature (Immunohistochemistry for SMA, ×100). (B) The tumor cells show a weak positive immunoreaction for desmin (Immunohistochemistry for desmin, ×100).