Subungual Amelanotic Melanoma Masquerading as Onychomycosis

Abstract

Subungual amelanotic melanoma is rare. In addition, amelanotic melanoma can mimic non-melanocytic tumors. A 67-year-old woman had a four-year history of dystrophy of the left fourth fingernail. Periodic acid-Schiff staining of the nail plate demonstrated fungal hyphae, establishing a diagnosis of tinea unguium. The nail plate subsequently detached and the underlying nail bed showed a red, friable mass that was biopsied and confirmed a diagnosis of melanoma. In conclusion, additional morphologic change of a persistent nail dystrophy—even with a biopsy-confirmed diagnosis of onychomycosis—may require consideration for repeat evaluation, including a biopsy, to exclude the possibility of a subungual malignant tumor.

Onychomycosis: An Updated Review

“…Differential diagnosis includes nail changes in psoriasis, lichen planus, alopecia areata, chronic dermatitis, onychogryphosis, chronic paronychia, pityriasis rubra pilaris, pachyonychia congenita, trachyonychia, onychogryphosis, median nail dystrophy, melanonychia striata, subungual melanoma, pemphigus vulgaris, pemphigoid, epidermolysis bullosa acquisita, bullous epidermolysis, subungual wart, subungual exostosis, subungual keratoacanthoma, rheumatoid arthritis, scleroderma, lupus erythematosus, scabies, tungiasis, twenty nail dystrophy, yellow nail syndrome, traumatic onychodystrophy, onychomatricoma, idiopathic onycholysis, porphyria, amyloidosis, myxoid cyst, fibroma, glomus tumor, Bowen disease, and squamous cell carcinoma [ 2 , 3 , 21 , 24 , 36 , 44 - 46 , 64 , 83 - 87 ].…”

Cutaneous Metastatic Breast Cancer Masked by Hidradenitis Suppurativa

“…When conditions of the hair, skin, and nails do not respond to appropriate medical therapy, additional evaluation should be considered to exclude the possibility of malignancy. A 67-year-old woman with biopsy-proven onychomycosis of a single fingernail did not respond to appropriate anti-fungal therapy; therefore, a nail avulsion was performed and the biopsy of the underlying friable red nodule has established the diagnosis of amelanotic melanoma [ 11 , 12 ]. Similar to the reported woman, Lookingbill et al described a patient who presented with a fluctuant and purulent draining perianal abscess that was initially diagnosed as hidradenitis suppurativa; a subsequent biopsy established the diagnosis of metastatic rectal mucinous adenocarcinoma [ 4 ].…”

“…Cutaneous metastasis from breast carcinoma can mimic the clinical presentation of other conditions [7][8][9][10][11][12]. A 30-year-old woman with hidradenitis suppurativa of the axilla, breast, and groin was noted to have a firm nodule on her right breast.…”

Subungual nail bed melanoma masquerading as tinea ungium

“…We recently also described a 67-year-old woman with a four-year history of persistent nail dystrophy of the left fourth fingernail [2]. Nail clipping was performed and periodic acid-Schiff staining of the nail plate demonstrated fungal hyphae, establishing a diagnosis of onychomycosis.…”