# Fibrous Hamartoma of Infancy of the Arm Mimicking a Vascular Malformation: A Diagnostic Pitfall

## TL;DR

A rare benign tumor in infants can look like a vascular malformation, leading to misdiagnosis, but surgical removal confirms the correct diagnosis and provides a cure.

## Contribution

This is the first reported case of fibrous hamartoma of infancy from Palestine, highlighting diagnostic challenges and the role of surgery.

## Key findings

- Fibrous hamartoma of infancy can mimic vascular malformations on MRI, leading to diagnostic confusion.
- Complete surgical excision confirmed the diagnosis and resulted in a full recovery with no recurrence.
- This case emphasizes the importance of considering FHI in differential diagnoses of pediatric soft tissue masses.

## Abstract

Fibrous hamartoma of infancy (FHI) is a rare benign soft tissue tumor of early childhood, often misdiagnosed due to its clinical and/or radiological resemblance to vascular malformations or pediatric soft tissue neoplasms.

A 7-month-old male presented with a rapidly enlarging, firm, non-pulsatile subcutaneous mass involving the anterior aspect of almost the entire right arm. MRI suggested a low-flow vascular malformation; however, due to clinical concern for alternative pathology and the lesion's benign appearance, large size, superficial location, and resectability, complete excision was performed. Histopathology revealed the characteristic triphasic pattern confirming fibrous hamartoma of infancy. The patient recovered well with no recurrence at 3-month follow-up.

This case highlights the diagnostic pitfalls of FHI, which may closely mimic vascular anomalies on imaging, and underscores the importance of surgical excision for both definitive diagnosis and curative treatment. To our knowledge, this represents the first reported case of FHI from Palestine.