# Recurrent Pediatric Extrapleural Solitary Fibrous Tumor of the Jaw

## TL;DR

A 13-year-old boy with a rare aggressive tumor in his jaw faced recurrence and died before a second surgery.

## Contribution

This case report highlights a rare extrapleural dedifferentiated solitary fibrous tumor in a pediatric patient.

## Key findings

- The tumor was confirmed via histopathology and immunohistochemistry as a dedifferentiated solitary fibrous tumor.
- The tumor recurred after initial surgical excision and the patient died before a second surgery.
- Immunohistochemical markers included CD34, STAT6, MyoD1, α-SMA, Bcl-2, and CD99.

## Abstract

Solitary fibrous tumors encompass a heterogeneous group of spindle cell neoplasms, ranging from biologically low-risk lesions to, in rare instances, highly aggressive tumors with malignant potential. Dedifferentiation in solitary fibrous tumors is uncommon and typically occurs in the retroperitoneum, with extrapleural involvement being among the least frequently reported.

A 13-year-old male presented with a rapidly enlarging mass in the lower jaw of 20 days duration, involving the submandibular triangle and floor of the mouth.

Histopathological examination of the excisional biopsy revealed spindle-shaped cells arranged in compact fascicles with a haphazard distribution, and areas of hyalinization. Immunohistochemical analysis demonstrated positivity for CD34, STAT6, MyoD1, α-SMA, Bcl-2, and CD99, confirming the diagnosis of extrapleural dedifferentiated solitary fibrous tumor (DSFT).

The lesion was surgically excised but recurred, likely due to disease progression. Re-excision was planned, but the child died 10 days before surgery.