engleski

Giant keratoacanthoma of the scalp in an elderly male patient

INTRODUCTION & OBJECTIVES: Keratoacanthoma (KA) is a neoplasm composed of keratinizing squamous cells that usually presents as a solitary, rapidly evolving, dome-shaped nodule with central keratin- filled crater. Due to its potential for spontaneous and complete regression, it has been considered a borderline or low- grade malignancy. Both clinically and histopathologically, KA can show overlapping features with squamous cell carcinoma. We present a case of a giant KA, a rare variant of this type of neoplasm. RESULTS: A 74-year old male with a history of psoriasis and excessive sun exposure presented with an asymptomatic, progressively growing lesion on the scalp. Physical examination revealed a plaque measuring 10x12 cm on the patient’s scalp vertex, with crusted, verrucous surface, elevated margins and slightly depressed central area comprising several foci of scarring. Multiple- site small incisional skin biopsies identified acanthotic and papillomatous epidermis, microabscesses of neutrophils and eosinophils but no evidence of malignancy. As this did not correlate with the clinical presentation, a subsequent larger biopsy was performed, which showed hyperkeratosis, epidermal hyperplasia with glassy-pink, large keratinocyte downgrowths, mild cellular atypia and rare mitoses at the deepest portions of the tumor, along with intraepidermal microabscesses and dermal inflammatory infiltrate containing eosinophils. The clinicopathological correlation supported a diagnosis of giant KA, although the final excisional specimen comprised also several areas indicative of verrucous carcinoma, a well-differentiated variant of squamous cell carcinoma (SCC). There was no regional lymphadenopathy and routine laboratory work-up was unremarkable. The patient was treated by radical surgical intervention and Thiersch-plasty. At the 6-month follow-up, multiple crusted lesions measuring up to 1 cm were noted at the periphery of the postsurgical scar and within the graft, indicating a recurrence. However, the patient opted not to undergo any active therapy at that point. CONCLUSIONS: This case presents a rare variant of KA with even a few foci of SCC arising within it. It also showcases the diagnostic pitfalls arising in the setting of small or superficial skin biopsies. Thus, a correlation of clinical findings and histopathology is oftentimes necessary to avoid misdiagnosis and undertreatment of KA and KA-like malignant neoplasms.

keratoacanthoma ; squamous cell carcinoma

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