Puzzling Papules over Face: Clinicians Perplexity - A Case of Squamous Cell Carcinoma Impersonating MolluscumContagiosum.

Sir,

Cutaneous Squamous cell carcinoma (cSCC) can present in various forms where as Molluscum contagiosum (MC) has been a master of disguise since its inception. cSCC is a malignant tumor and arises from epidermal keratinocytes.[1] In fair-skinned individuals, it is known to develop in photo damaged areas of skin manifesting as variable cutaneous lesions including papules, plaques, or nodules, that can be smooth, hyperkeratotic or ulcerated.[2] Molluscum contagiosum (MC) is a self-limiting, infectious dermatoses caused by molluscum contagiosum virus (MCV) of Poxviridae family. It is frequently seen in children, sexually active adults and immunocompromised individuals. It classically presents as firm, dome-shaped, pink or skin-colored papules with a shiny and umbilicated surface. The diagnosis is mainly clinical.[3] Dermoscopy and skin biopsy can be done for confirmation of diagnosis. We hereby report a case of cSSC presenting as multiple umbilicated papules over face impersonating molluscum contagiosum. A 60-year-old male presented to us with multiple, asymptomatic erythematous to skin colored dome-shaped waxy, shiny papules with central umbilication due to central pits, firm in consistency present over lips and chin over face since 2 months [Figure 1a and b]. On general examination there was no regional lymphadenopathy. Systemic examination was within normal limits. On detailed enquiry patient revealed history of painful oral ulcer 1 year back which on biopsy was diagnosed as squamous cell carcinoma of oral cavity and he had underwent excision with post-operative chemotherapy for the same. Present lesions appeared 2 months after the patient was successfully treated for oral squamous cell carcinoma and was not on any treatment during those 2 months. Patient denied history of trauma or pre-existing dermatoses at the site. Laboratory data including anti-retrovirus antibody tests were all within normal limits. We performed extraction on single lesion to look for molluscum bodies. Expressed core from the lesion was not typical of molluscum. Dermoscopy could not be performed. Punch biopsy was done from a typically looking MC lesions with a puncta and other from an atypical papule. Microscopically, H and E stained section of skin biopsy showed presence of sheets of malignant cells within dermis consistent with squamous cell carcinoma. The epidermis was unremarkable [Figure 2]. For further evaluation and management patient was referred to a surgeon after which patient didn't follow up further to us. Cutaneous SCC is one of the most common malignancies worldwide, with an increasing incidence. It is important to distinguish well-differentiated cSCC from several other benign and reactive squamoproliferative lesions to avoid diagnostic pitfalls.[2] Squamous cell carcinoma frequently arises in skin which is chronically exposed to ultraviolet radiation. SCC may be mistaken for actinic keratosis, Bowen's disease, keratoacanthoma, Basal cell carcinoma, melanoma, cutaneous horn and blastomycosis[4] whereas MC may be mistaken for malignancies such as SCC, basal cell carcinoma (BCC) and sebaceous carcinoma. MC also acts as a marker of immunosuppression associated with internal malignancy.[5] The SCC in this patient closely resembled MC. In our case malignant tumor was mimicking a viral infection. This case highlights the importance of biopsy of skin lesions for accurate early diagnosis and better management of the patient that may have been erroneously misdiagnosed as MC. Also even after extensive literature search we could find only a single reference describing similar diagnostic dilemma but they reported patient with both SCC and MC.[5] The patient reported here only had SCC which could have been easily mistaken for MC.

Figure 1

(a) Multiple shiny papule with central umbilication present over chin and face. (b) Shiny, waxy papule with central umbilication (red arrow)

Figure 2

Presence of sheets of well differentiated squamous carcinoma cells (white arrow) scattered throughout within dermis showing pleomorphic cells (H&E, x400)

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Conflicts of interest

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