Furuncular Myiasis Mimicking an Epidermal Inclusion Cyst of the Scalp: A Case Report and Focused Review of Diagnostic Pitfalls in Scalp Myiasis.

Furuncular myiasis of the scalp may closely mimic common cystic scalp lesions, including pilar and epidermal inclusion cysts, leading to delayed diagnosis and inappropriate treatment. We report the case of a 67-year-old man who presented with a painful right parietal scalp nodule that was initially diagnosed as a pilar cyst or epidermal inclusion cyst. Mild discharge, erythema, and inflammation partially improved following a two-week course of oral doxycycline; however, persistent pain prompted the patient to pursue surgical excision. Histopathologic examination revealed findings consistent with furuncular myiasis. At postoperative follow-up, additional history revealed recent travel to Costa Rica with outdoor exposure, including hiking and ATV riding. To better characterize diagnostic pitfalls associated with scalp myiasis, we conducted a focused review of published cases, with an emphasis on initial misdiagnoses, diagnostic methods, and management approaches. Reported cases were mistaken for sebaceous cysts, epidermal inclusion cysts, furunculosis, abscesses, cellulitis, infected insect bites, and, less commonly, osteomyelitis. Diagnosis was established through several approaches, including clinical recognition, ultrasound, histopathologic examination, the direct visualization of larvae, and the reconsideration of the clinical history. We summarize selected published cases, along with their initial diagnoses, diagnostic methods, and management strategies, in a table to highlight recurring diagnostic pitfalls. This case report and focused review demonstrate that scalp myiasis remains an important mimic of common cystic scalp lesions. Clinicians should consider myiasis in patients with painful scalp nodules, central puncta, incomplete response to antibiotic therapy, and relevant travel exposure. Although the lesion in our patient was clinically favored to represent a benign cystic process, definitive diagnosis was not possible on examination alone. Excision and subsequent histopathologic evaluation established an unexpected diagnosis and facilitated appropriate management.