Synonyms

• Sinus histiocytosis with massive lymphadenopathy
• SHML

Category

Syndrome

Gender

Both equally

Epidemiology

• Benign histiocytic disorder
• Peak incidence in 1st-2nd decades (juvenile form) or older adults
• African ancestry predominance
• Can involve Bone and soft tissues

Clinical Features

• Massive lymphadenopathy
• Fever, weight loss
• Bone pain if skeletal involvement

Location

• Lymph nodes (mediastinal, cervical)
• Bone and soft tissues less common but can occur

Imaging

• CT: massive mediastinal/cervical lymphadenopathy
• MRI: characterises extent

Pathology

• Sheets of histiocytes with phagocytosed material
• S100+, CD68+
• Benign course

Genetics

• Sporadic or familial
• SLC29A3 mutations in some

Treatment

• Observation for asymptomatic disease
• Chemotherapy or radiotherapy for symptomatic disease

Prognosis

• Generally excellent - self-limited disease
• 50% spontaneous regression
• Others require treatment

Key Points

• Benign histiocytic disorder
• Often self-limited
• Resembles malignancy clinically but Benign

Workup - Blood Tests

FBC, U&E, LFTs - baseline

Workup - Local Imaging

• CT chest/abdomen/pelvis - assess extent
• MRI if soft tissue/Bone involvement

Workup - Biopsy

• Confirm diagnosis via excision or biopsy
• Histology and immunophenotype diagnostic

Workup - Staging

Assess systemic involvement