Volar Melanotic Macules in a Gardener: A Case Report and Review of the Literature

Abstract

Volar melanotic macules are asymptomatic, tan-brown to brownish-black macules found on the palms, fingers, soles, and/or toes of dark-skinned individuals and are infrequently reported in light-skinned individuals. Herein, we report the acquisition of multiple, brownish-black volar digital macules in a 63-year-old white woman and avid gardener that were noted after the onset of pruritic, chronic hand dermatitis over a 10-month period. She was healthy without any medical conditions or medications. No family history of intestinal polyposis or mucosal melanosis existed. At presentation, she had less than 20 brownish-black, 2- to 10-mm irregular macules over the volar aspect of the thumbs and index fingers, left greater than right hand, associated with erythema, scale, and a negative potassium hydroxide examination. In addition, she had melanotic macules of her lips, buccal mucosa, and conjuctiva. No nail or anogenital macules were found. Biopsy demonstrated a region of epidermal hyperplasia, hyperkeratosis, and interface dermatitis associated with melanophages and sparse lymphocytic infiltrate. Melanin staining revealed diffuse pan-epidermal hypermelanization, dermal melanin, and dendritic melanocytes, which expressed HMB-45. After 1-year follow-up and treatment with topical corticosteroid, the volar macules have faded to tan brown. Based on the location, avocation, and coexisting mucosal melanotic macules, an irritant phytodermatitis with postinflammatory hyperpigmentation was diagnosed in the setting of Laugier-Hunziker syndrome-a disorder denoted by macular hyperpigmentation of nail, volar, and/or mucosal surfaces in healthy adults. Volar melanotic macules can also complicate 5-flourouracil therapy, tinea pedis, and other inflammatory disorders; be associated with acral melanomas; or represent a cutaneous manifestation of systemic disease such as Addison disease, Peutz-Jegher syndrome, Leopard syndrome, Carney syndrome, AIDS, and neurofibromatosis.

A black tongue in a young woman

“…Clinical conditions mimicking the oral pigmentation of AD include black hairy tongue, ethnic pigmentation, reactions to certain drugs (e.g. minocycline), Laugier–Hunzinker syndrome and Peutz–Jeghers syndrome 5 …”

Mystery behind labial and oral melanotic macules: Clinical, dermoscopic and pathological aspects of Laugier-Hunziker syndrome

“…An atypical report described slight cellular atypia of intraepidermal melanocytes in a sun-exposed skin lesion[ 51 ]. Acanthosis[ 6 , 13 , 17 , 22 , 42 , 44 , 70 , 81 , 86 , 88 ], hyperkeratosis[ 60 , 70 , 81 , 86 ], hyperparakeratosis[ 6 , 88 ], or spongiosis[ 13 , 53 ] of the epithelium and elongated rete ridges[ 6 , 32 , 81 , 88 ] have been noted in some reported cases.…”

Macular pigmentation complicating irritant contact dermatitis and viral warts in Laugier-Hunziker syndrome

“…1,2,4,[6][7][8] Digital melanotic macules have been described in a 63-year-old gardener with irritant phytodermatitis and LHS. 6 Furthermore, a pigmented macule has been reported on a psoriatic plaque on the elbow of a patient with LHS. 7 None of the other case reports describe an associated inflammatory dermatosis.…”

“…One patient with LHS developed large diffuse hyperpigmentation on the right pretibial area . Six cases of finger pigmentation have been described . Digital melanotic macules have been described in a 63‐year‐old gardener with irritant phytodermatitis and LHS .…”

“…Six cases of finger pigmentation have been described . Digital melanotic macules have been described in a 63‐year‐old gardener with irritant phytodermatitis and LHS . Furthermore, a pigmented macule has been reported on a psoriatic plaque on the elbow of a patient with LHS .…”