Sir,

A one-year-old girl presented with a reddish nodule in the gluteal cleft, which had gradually enlarged over four months. The lesion further increased in size one month prior to her initial visit, prompting referral for evaluation. She had no history of immunodeficiency, and her development was normal. Physical examination revealed an 18 x 7 mm elastic, soft, red nodule in the gluteal cleft with visible yellowish-white contents (Fig. 1). Additionally, several smaller, dome-shaped papules (2-3 mm) with central umbilication and glossy white surfaces were scattered across the buttocks, perineum, and thighs.

Figure 1: Clinical image showing a soft, reddish nodule with visible yellowish-white contents in the gluteal cleft.

Dermoscopy of the large nodule showed multiple pearly yellowish-white structures on its surface (Fig. 2). The differential diagnosis included granuloma gluteale infantum, juvenile xanthogranuloma, and molluscum contagiosum (MC). A biopsy of the large nodule revealed acanthosis and the presence of intracytoplasmic inclusion bodies, both eosinophilic and basophilic, within keratinocytes. Inflammatory cell infiltration and granulomatous inflammation were observed in the dermis (Fig. 3), confirming the diagnosis of molluscum contagiosum with associated granulomatous inflammation.

	Figure 2: Dermoscopy of the nodule revealing multiple pearly yellowish-white structures on the surface.
	Figure 3: Histopathology showing epidermal acanthosis, intracytoplasmic eosinophilic and basophilic inclusion bodies, and dermal granulomatous inflammation (H&E, 40x).

Intriguingly, the large gluteal nodule regressed spontaneously six weeks after the biopsy without additional treatment, and some of the surrounding papules also showed signs of regression during this period. This synchronous regression suggests a systemic or coordinated local immune response. Previous reports have suggested that trauma, including partial excision or biopsy, can sometimes induce the resolution of MC by disrupting the viral microenvironment and promoting immune recognition [1]. In addition, a case of MC in an HIV-infected patient was reported to show a xanthogranuloma-like reaction, supporting the idea that host immune activation may lead to atypical inflammatory responses to MC [2]. Similarly, as it is in infants or immunologically immature individuals, the granulomatous reaction observed in that case likely reflected an immune response to the virus. The biopsy may have enhanced this response, ultimately contributing to lesion regression.

MC is caused by molluscum contagiosum virus, a poxvirus that infects epidermal keratinocytes [3]. While typical lesions are 2–5 mm dome-shaped, skin-colored to pink papules, with central umbilication, atypical large nodules may occur in intertriginous areas due to autoinoculation, maceration, or barrier dysfunction [1,4]. In this case, the gluteal cleft may have provided a favorable environment for such an atypical presentation. In such an atypical presentation, where the lesion manifests as a large nodule with granulomatous inflammation, careful monitoring of the clinical course is essential, as the inflammatory response may influence both diagnosis and management. Although dermoscopic features of giant MC in the perianal area have been reported, such as the presence of grouped white, shiny clods, that case did not show histopathological evidence of granulomatous inflammation [5]. In contrast, that case was characterized by both distinctive dermoscopic findings and a pronounced granulomatous reaction in the dermis. The pearly white structures seen on dermoscopy likely corresponded to clusters of viral inclusion bodies, while the reddish areas may have reflected underlying dermal granulomatous inflammation, which may have contributed to the formation of a large atypical nodule in the gluteal cleft.

REFERENCES

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2.Aldabagh B, Ly MN, Hessel AB, Usmani AS. Molluscum contagiosum involving an epidermoid cyst with xanthogranuloma-like reaction in an HIV-infected patient. J Cutan Pathol. 2010;37:282-6.

3.Casanova-Esquembre A, Lorca Sprohnle J, Partarrieu-Mejias F, Alegre-de-Miquel V. Molluscum contagiosum induced reverse isotopic phenomenon. Actas Dermosifiliogr. 2023;114:449-51.

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