A five-year-old child with a subcutaneous forehead nodule.

Area of Science:

• Medical Parasitology
• Pediatric Dermatology
• Tropical Medicine

Background:

• Onchocerciasis, also known as river blindness, is a parasitic disease caused by the nematode Onchocerca volvulus.
• While endemic in parts of Africa and the Americas, imported cases can occur in non-endemic regions.
• Pediatric presentations of onchocerciasis, particularly subcutaneous nodules, are less common and can mimic other conditions.

Observation:

• A 5-year-old female patient adopted from Ethiopia presented with a firm, raised nodule on her forehead.
• Initial differential diagnoses included Langerhans cell histiocytosis with bone involvement.
• Histopathologic examination of the excised nodule was performed.

Findings:

• Histopathology confirmed the presence of a young-adult, female Onchocerca volvulus worm within the nodule.
• The findings ruled out Langerhans cell histiocytosis.
• Microscopic identification of the parasite was key to the diagnosis.

Implications:

• This case underscores the importance of considering onchocerciasis in pediatric patients presenting with subcutaneous nodules, especially those with a history of travel from endemic areas.
• Recognizing the morphologic characteristics of Onchocerca volvulus in non-endemic settings is vital for accurate diagnosis and appropriate clinical management.
• Increased awareness among clinicians can lead to earlier detection and intervention, potentially improving patient outcomes and preventing misdiagnosis.