A Spindle Cell Tumor in Disguise: Histoid Nodules Arising From Peripheral Nerves

Area of Science:

• Dermatology
• Infectious Diseases
• Neurology

Background:

• Leprosy, a chronic infectious disease, primarily affects the skin, peripheral nerves, and upper respiratory tract.
• Histoid leprosy is a rare, distinct form characterized by subcutaneous nodules resembling histiocytomas.
• Neural involvement is a key feature, often presenting as thickened nerves.

Observation:

• A 25-year-old male presented with multiple, painless, 5-6 mm subcutaneous nodules linked to thickened superficial cutaneous nerves.
• Nodular infiltration of the earlobe was also noted.
• Ultrasonography showed well-defined, avascular, heterogeneous, hypoechoic lesions over focally thickened nerves.

Findings:

• Histopathology revealed spindle-shaped histiocytes in a storiform pattern.
• Numerous acid-fast bacilli were identified using Fite-Faraco staining.
• Skin slit smear demonstrated a high bacteriological index (+6).

Implications:

• This case underscores the importance of considering rare leprosy forms, like neural histoid leprosy, in differential diagnoses.
• Accurate histopathological and imaging findings are crucial for diagnosing atypical presentations.
• Early and correct diagnosis is vital for effective treatment and preventing nerve damage in leprosy.