An Unusual Complication of Nevus Sebaceous Debugged!

Dear Editor, Nevus sebaceous is an uncommon, congenital hamartoma that arises from hyperplasia of epithelial, sebaceous, follicular, and apocrine components of the skin.[1] Myiasis refers to the infestation of living humans and vertebrate animals by flies of dipterous larvae commonly found in the tropics and subtropics.[2] Cutaneous myiasis is associated with several dermatological conditions. In this article, we describe a case of myiasis in a patient with nevus sebaceous, a hitherto unreported complication. A 20-year-old male presented with a long-standing lesion over the neck, which was noticed since birth. He provided history of spontaneous ulceration of the lesion in the preceding weeks, which roughly coincided with the period following varicella infection as reported by the patient. On examination, a 4 × 5 cm ulcer, with irregular margins was noted on the left side of the neck. The floor had multiple maggots and purulent discharge, and the edge of the ulcer showed verrucous prominences focally. [Figure 1a] Tenderness and local rise of temperature were present. Cervical lymphadenopathy was present. The rest of the cutaneous examination was normal. Systemic examination was non-contributory.Figure 1: (a) A 4 × 5 cm ulcer over left side of the neck, with maggots on the floor and verrucous prominences at the periphery (b) Older photograph showing verrucous plaque over left side of the neckThe patient denied any history of manipulation of the ulcer. Upon further inquiry, he presented older photographs displaying the lesion, revealing a verrucous plaque that clinically indicated nevus sebaceous or verrucous epidermal nevus. [Figure 1b] The baseline hematological investigations revealed hemoglobin of 8.5g/dL with a microcytic hypochromic picture consistent with iron deficiency anemia. The wound swab showed scanty growth of Enterococcus faecium. Computed tomography (CT) neck showed inflammatory soft tissue thickening extending to sternocleidomastoid muscle, and cervical lymphadenopathy, with no evidence of malignancy. Skin biopsy done from the margin of the lesion revealed the following features: papillomatosis, compact orthokeratosis, parakeratosis, uneven psoriasiform acanthosis, and ulceration in the epidermis. Dermis showed small sebaceous glands opening directly on the surface and abortive germ cells—consistent with nevus sebaceous. [Figure 2a] Section of the larvae showed cuticle, external cuticular spines, and striated muscles. [Figure 2b].Figure 2: (a) Sebaceous glands opening directly onto the surface of skin (black arrow)–consistent with nevus sebaceous (H and E; 40X) (b) Section of botfly larvae-external cuticular spines (black arrows), salivary glands (blue arrow), cuticle (red arrow), striated muscle (yellow asterisk), chitinous wall (red asterisk) (H and E; 40X)The patient was started on systemic antibiotics, and underwent surgical debridement and daily turpentine dressings, with the removal of all the maggots, and the wound healed by primary intention. [Figure 3a and b].Figure 3: (a) Lesion post-surgical debridement and removal of maggots (b) Healed lesion–3 months after surgical debridementNevus sebaceous, also called organoid nevus, Jadassohn nevus, or pilosyringosebaceous nevus, was first described by Jadassohn in 1895.[3] It can present at birth or thereafter, and is divided into three stages based on the morphological appearance and age group of the affected individual. It manifests as linear to oval-shaped plaques, with partial or complete alopecia, and can range from skin colored, to yellowish-orange or brownish-black color. Surface of the plaques can be smooth or verrucous, depending on the development and stage of the lesion.[1] The commonly affected sites include scalp, preauricular area, face, and neck.[1] Myiasis refers to the infestation of living humans and vertebrate animals by dipterous larvae.[2] Cutaneous myiasis is the most common clinical variant, and can be divided into three main clinical types: furuncular, creeping (migratory), and wound (traumatic).[4] Numerous dermatological disorders like neuropathic ulcers, psoriasis, seborrheic keratosis, onychomycosis, vascular insufficiency ulcers, cutaneous B cell lymphoma, basal cell carcinoma, lipedema, herpes zoster, cancrum oris, filarial lymphedema, condyloma acuminatum, hemorrhoid, leprosy, pediculosis, impetigo, carcinomatous ulcers and ulcerated genital seborrheic keratosis have been reported to be associated with wound myiasis.[2,5] Treatment includes expression of the larvae after placing an obstructing substance over the spiracle, irrigation and debridement, and surgical exploration. Topical and/or systemic antibiotics should be given to prevent secondary infection.[4] Predisposing factors for infestation by maggot-producing flies include summer season, contact with infested hosts or visiting an area inhabited by infested hosts, sleeping outdoors, poor personal hygiene and poor treatment of wounds, homelessness, and travel to an endemic area.[5] Dermatological conditions are also known risk factors, particularly ulcerative and hyperkeratotic lesions.[2] Prior reports of ulceration in nevus sebaceous usually indicated neoplastic change, either benign or malignant.[6] The lesion’s hyperkeratotic and ulcerated surface, accessibility, and neglect are factors that are hypothesized to have contributed to our patient’s condition. A PubMed search of the English language literature using the search terms “Nevus Sebaceous” and “Myiasis” failed to reveal prior reports, which prompted us to publish this unusual case. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.