A Red Lobulated Facial Mass: A Clinicopathological Challenge

Area of Science:

• Dermatology
• Pathology
• Oncology

Background:

• Rosai-Dorfman disease (RDD) is a rare benign histiocytic proliferative disorder.
• Facial nodules are a common presentation, posing diagnostic and therapeutic challenges.
• Differential diagnoses include adult-onset xanthogranuloma, sarcoidosis, and anaplastic large cell lymphoma.

Purpose of the Study:

• To report a rare case of adult-onset RDD presenting as a progressive facial nodule.
• To emphasize the diagnostic utility of histopathology and immunohistochemistry in RDD.
• To highlight the efficacy of a combined therapeutic approach.

Main Methods:

• Histopathological examination with S100 staining and assessment for emperipolesis.
• Immunohistochemistry to differentiate from other histiocytic disorders.
• Treatment with systemic dapsone and serial surgical excisions.

Main Results:

• Histopathology confirmed RDD with S100-positive histiocytes exhibiting emperipolesis.
• The patient showed significant regression of the facial nodule with systemic dapsone (100 mg daily) over 1.5 years.
• Complete clearance was achieved after serial excision of the residual lesion.

Conclusions:

• RDD is characterized by S100+ histiocytes with emperipolesis.
• Systemic dapsone combined with serial surgical excisions can be an effective treatment for facial RDD.
• Early and accurate diagnosis is crucial for appropriate management of RDD.