Rapidly growing subcutaneous mass in an infant

Area of Science:

• Pediatric Oncology
• Pediatric Pathology
• Soft Tissue Tumors

Background:

• Fibrous hamartoma of infancy (FHI) is a rare benign mesenchymal tumor affecting young children.
• FHI presents a broad clinical differential diagnosis, frequently being mistaken for vascular or malignant soft tissue neoplasms.
• Accurate diagnosis is crucial due to potential clinical confusion with aggressive tumors.

Observation:

• This report details a rare case of fibrous hamartoma of infancy.
• The case includes comprehensive clinical, radiologic, and histologic findings.
• The observed patient presented with characteristic features of this uncommon condition.

Findings:

• Fibrous hamartoma of infancy is characterized by a unique triphasic histological pattern.
• This pattern consists of mature adipose tissue, mature fibrous tissue, and immature mesenchymal tissue.
• Histologic recognition of these components is essential for definitive diagnosis.

Implications:

• Correctly identifying FHI ensures appropriate patient management and avoids unnecessary aggressive treatments.
• Understanding FHI's histology aids in differentiating it from concerning soft tissue malignancies in pediatric patients.
• This case contributes to the literature on rare pediatric tumors, enhancing diagnostic accuracy.