Isolated giant molluscum contagiosum mimicking epidermoid cyst.

Molluscum contagiosum is a benign cutaneous viral infection which is caused by double- stranded DNA poxvirus. It affects mainly children and young adults and usually presents with single or multiple umblicated papules or nodules on face, arms, legs and anogenital regions. It may present in atypical size and clinical appearance in patients with altered or impaired immunity and rarely in immuncompetent patients. Herein we present an immuncompetent young adult patient with isolated giant molluscum contagiosum, which was mimicking epidermoid cyst clinically.

Introduction

Molluscum contagiosum is a double-stranded DNA virus, which is the cause of benign, infectious disease of the skin that is characterized by dome-shaped papules with a central dell or depression clinically [1]. In patients with altered or impaired immunity such as atopic dermatitis, after long term corticosteroid and immunosuppressive therapy use, sarcoidosis, leukemias, Wiskott-Aldrich syndrome and especially with acquired immune deficiency syndrome, atypical lesions of molluscum contagiosum may occur, often reaching a large size on an unusual site that can also mimic a wide spectrum of other conditions [2]. The presence of giant molluscum contagiosum in immunocompetent patients is rare, and in some reviews it was reported to be a clue for HIV infection in both the pediatric patient group and adult patients [3]. This rare infection must be kept in mind in patients who have solitary pink nodular lesions for a short time, especially on face and anogenital region.

Case report

A 27-year-old male was admitted to our outpatient clinic with a 4-month history of a 1.5 cm in diameter, asymptomatic, pink nodular lesion on left temporal region (Figure 1). He had no systemic disease or drug use history. In dermatological examination a white material output was detected. Dermoscopic examination revealed white-yellow structureless area in the center of the of lesion and increased linear vascularity on the periphery (Figure 2). Excisional biopsy was offered with preliminary diagnosis of epidermoid cyst and isolated giant molluscum. Histopathologically epidermal hyperkeratosis, acanthosis, widespread viral cytopathic effect and intracytoplasmic inclusion bodies were seen (Figure 3). He was diagnosed with isolated giant molluscum with his clinical and histopathological findings. His laboratory tests for immunsuppresssion, including complete blood counting, immunoglobulins and HIV serology were totally normal. No recurrence was detected on the 6-month control visit.

Figure 1.

A 1.5 cm diameter, asymptomatic, pink tumoral lesion on left temporal region. [Copyright: ©2016 Uzuncakmak et al.]

Figure 2.

White-yellow structureless area in the center of the lesion and increased linear vascularity on the periphery. [Copyright: ©2016 Uzuncakmak et al.]

Figure 3.

Epidermal hyperkeratosis, acanthosis, widespread viral cytopathic appearance and intracytoplasmic inclusion bodies. [Copyright: ©2016 Uzuncakmak et al.]

Discussion

Molluscum contagiosum (MC) is a common infectious disease of the skin characterized by pearly dome-shaped papules with a central dell or depression located on the face, arms, legs and anogenital region, caused by the molluscum contagiosum virus [1]. The virus replicates in the epidermis and enters the skin from a small skin defect leading to impaired skin barrier function or from contaminated items, such as towels or clothes. Specific lesions of MC are usually smaller than 5 mm and less than 20 in number [1-4]. Although it is known to be a disease of childhood, rarely it can be seen in adults. Due to the characteristic appearance of the lesions, diagnosis is generally made without laboratory testing. Specific treatments or therapies are usually not administered for molluscum contagiosum infection in immunocompetent individuals, as lesions will resolve within time.

Dermoscopic examination may be helpful in atypical cases. Dermoscopy of MC reveals a central pore or umbilication in association with polylobular white to yellowish amorphous structures, which are surrounded by linear, fine, corona-like telangiectasias [5,6] This apperance may change in atypical cases, especially in atypical localizations. Histopathologic examination is mandatory in these cases.

Giant MC is a rare nodular variant of molluscum contagiosum, which is 0.5–1 cm or more in diameter. This clinical presentation may mimic basal cell carcinoma, furuncle, intradermal nevus, amelanotic melanoma, kerathoacanthoma and viral warts [2,3]. These lesions are rare in healthy children or adults and may accompany altered immunity, such as atopic dermatitis, corticosteroid and immunosuppressive therapy, sarcoidosis, leukemias, Wiskott-Aldrich syndrome and acquired immune deficiency syndrome. Atypical lesions of molluscum contagiosum may occur often and reach large size with extensive distribution on unusual body parts [3,4,7].

In our patient there was no systemic disease, drug usage, immundeficiency or atopic dermatitis history. There are only a few case reports of giant molluscum contagiosum occurring in immunocompetent patients in the literature [2,7]. Most of these patients are children without immunodeficiency. There are also only a few case reports of molluscum contagiosum on the scalp in immunocompetent patients—one newborn and one elderly patient. Our patient was a young immunocompetent adult patient.

Cryotherapy, 10% KOH application, trichloroacetic acid, imiqumod, systemic cimetidin, intralesional 5-FU and bleomycin and total excision are the main treatment options [1,2]. We chose total excision surgery in our patient to exclude epidermoid cyst histologically.

We present this case to present giant molluscum in differential diagnosis of soft, slowly growing tumoral lesions with atypical presentation.