# Malignant high-grade unclassifiable spindle cell sarcoma in the hand: A diagnostic and therapeutic challenge

## TL;DR

A rare case of high-grade spindle cell sarcoma in the hand is presented, emphasizing the need for accurate diagnosis and careful surgical treatment to preserve function.

## Contribution

This case demonstrates the successful complete resection of a complex spindle cell sarcoma while preserving hand function.

## Key findings

- Histopathological analysis confirmed high-grade spindle cell sarcoma despite initial biopsy suggesting dermatofibroma.
- The patient remained recurrence-free at 10 months with preserved hand function after surgical resection.
- Immunohistochemistry showed positivity for CD99 and CD56, with multiple other markers negative.

## Abstract

Introduction: Spindle cell sarcoma is a rare malignancy characterized by spindle-shaped cells, often mimicking other tumors and posing diagnostic challenges due to its nonspecific clinical features. This case highlights the importance of a multidisciplinary approach and demonstrates the feasibility of complete tumor resection with functional preservation, even in large and complex tumors.

Case Presentation: A 51-year-old woman with no significant medical history presented with a large, exophytic mass on her left hand, causing notable functional impairment in daily activities. Physical examination revealed a rubbery mass, measuring 15 × 8 cm. Imaging studies, including radiography, computed tomography, and magnetic resonance imaging, were performed. Given the impact of grasp functionality on daily life, surgical resection was scheduled. The excised tissue was subsequently submitted for histopathological evaluation.

Results: Imaging demonstrated a vascularized mass without bone involvement. Initial biopsy suggested multicentric cellular dermatofibroma. However, histopathological examination of the excised specimen revealed findings consistent with high-grade spindle cell sarcoma. Immunohistochemistry showed positivity for CD99 and CD56, with negative markers for S-100, factor XIII, TLE-1, CD34, SOX10, H3K27ME, SS18 and actin. At the 10-month follow-up, she remained recurrence-free with preserved hand function.

Conclusions: A meticulous surgical approach is vital for the management of the balance of complete tumor excision and preservation of hand function. A thorough histopathological examination is necessary for diagnosis. Collaboration across disciplines is key to improving treatment outcomes.