Sinus histiocytosis with massive lymphadenopathy

Area of Science:

• Pediatric Pathology
• Histiocytic Disorders
• Benign Neoplasms

Background:

• Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare, benign proliferative disorder of unknown etiology.
• It typically manifests as painless, massive cervical lymphadenopathy, often affecting extranodal sites.
• While generally self-limiting, SHML can present with diverse clinical features.

Observation:

• A 22-month-old child presented with severe respiratory distress (stridor) and difficulty swallowing (dysphagia).
• Imaging revealed a retropharyngeal mass alongside massive cervical adenopathy.
• Biopsies confirmed the diagnosis of sinus histiocytosis with massive lymphadenopathy.

Findings:

• This case highlights pharyngeal involvement as an atypical presentation of SHML.
• Pharyngeal masses in SHML can lead to critical airway compromise and feeding difficulties in pediatric patients.
• The histological findings were characteristic of SHML, despite the unusual location.

Implications:

• Recognizing pharyngeal involvement in SHML is crucial for prompt diagnosis and management of airway obstruction.
• The heterogeneity of SHML presentation underscores the need for clinical vigilance.
• Understanding the natural course of SHML, including spontaneous resolution, guides treatment decisions.