[Sinus histiocytosis with massive lymphadenopathy].

Area of Science:

• Pediatric Pathology
• Dermatopathology
• Hematopathology

Background:

• Sinus histiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease, is a rare benign proliferative disorder.
• It typically affects lymph nodes but can manifest with extranodal involvement, including subcutaneous tissues.
• Understanding its varied presentations is crucial for accurate diagnosis.

Observation:

• A 13-year-old male presented with multiple subcutaneous tumor-like formations.
• These lesions had a 7-month course without significant impact on his general condition.
• Laboratory findings included mild anemia and elevated erythrocyte sedimentation rate (ESR).

Findings:

• Microscopic examination revealed dense infiltrates of lymphoid cells, plasma cells, and histiocytes-macrophages.
• Foci of fibrosis and xanthomatosis were present within the lesions.
• The histological features of SHML can mimic neoplastic conditions of hematopoietic and lymphoid tissues.

Implications:

• Accurate differential diagnosis is essential to distinguish SHML from malignant conditions such as lymphoma or histiocytosis X.
• This case highlights the importance of integrating clinical, radiological, and pathological findings.
• Recognition of SHML's potential to mimic tumors aids in appropriate patient management and avoids unnecessary aggressive therapies.