Overview
Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor predominantly affecting young adults and children, characterized by a distinctive biphasic pattern of spindle cells and epithelioid histiocytes within a myxoid stroma. 1Diagnosis
Morphological Features: Biphasic pattern with spindle cells and epithelioid histiocytoid areas.
Immunohistochemistry: Positive for TLE1, CD99, and EMA; negative for SYT rearrangement.
Molecular Testing: Fluorescence in situ hybridization (FISH) for EWSR1 gene rearrangement supports diagnosis.
Differential Diagnosis: Consider AFH in cases with spindle cell morphology and positive TLE1, CD99, and EMA, especially when synovial sarcoma is suspected.
Biopsy Evaluation: Core biopsy findings may initially suggest synovial sarcoma due to overlapping features. 1Management
Surgical Resection: Primary treatment involves complete surgical excision with clear margins.
Adjuvant Therapy: Not routinely indicated for localized disease; consider based on risk factors and tumor characteristics.
Follow-Up: Regular imaging and clinical monitoring to assess for recurrence or metastasis.Special Populations
Pediatrics: AFH is commonly encountered in children, emphasizing the importance of accurate diagnosis and surgical management. 1Key Recommendations
Include AFH in the differential diagnosis when evaluating spindle cell tumors with positive TLE1, CD99, and EMA immunostaining, especially in pediatric patients. (Evidence: Moderate) 1
Perform FISH for EWSR1 gene rearrangement to differentiate AFH from synovial sarcoma in cases with overlapping morphology and immunohistochemistry. (Evidence: Moderate) 1
Primary treatment for AFH should focus on complete surgical resection; adjuvant therapies are not routinely recommended for localized disease. (Evidence: Expert opinion) 1References
1 Zaccarini DJ, Naous R, Sheth Y, El-Zammar O, de la Roza G, Curtiss CM. TLE-1-Positive Angiomatoid Fibrous Histiocytoma Mimicking Synovial Sarcoma. Applied immunohistochemistry & molecular morphology : AIMM 2019. link