# Adult Primary Hepatic Sarcoma Presenting as a Chronic Expanding Hematoma

## TL;DR

A rare case of adult primary hepatic sarcoma was initially mistaken for a benign hematoma but later revealed aggressive cancer behavior.

## Contribution

This case highlights the diagnostic challenge of distinguishing hepatic sarcoma from benign hemorrhagic lesions.

## Key findings

- The lesion initially diagnosed as a chronic expanding hematoma was later identified as undifferentiated sarcoma.
- Rapid peritoneal dissemination occurred nine months after initial surgery.
- Histopathological review confirmed malignant spindle-shaped tumor cells in both specimens.

## Abstract

Primary hepatic sarcoma is extremely rare in adults and can be difficult to distinguish from benign hemorrhagic lesions on imaging. We report a rare case of undifferentiated sarcoma (US) that initially mimicked chronic expanding hematoma (CEH) and ruptured.

A woman in her 50s presented with sudden-onset abdominal pain caused by rupture of a hepatic lesion diagnosed radiologically as CEH and underwent right hepatectomy. Preoperative imaging demonstrated a well-circumscribed hypodense mass with rich arterial vascularity and MRI findings suggestive of mixed old and recent hematoma. Nine months later, rapidly progressive peritoneal dissemination developed and was surgically evacuated. Histopathological examination of the disseminated lesions revealed US, and retrospective review of the initial specimen identified similar spindle-shaped tumor cells beneath the fibrous capsule.

This case illustrates that hepatic lesions resembling CEH may represent or develop into US. Rupture and atypical clinical progression should raise suspicion for malignancy, and careful histopathological assessment of subcapsular tissue is essential.