Verrucous growth on the glans penis: A clinical conundrum!

Question

What is your diagnosis?

Answer

Diagnosis: Pseudoepitheliomatous Keratotic and Micaceous Balanitis (PKMB)

Discussion

PKMB is a rare non-venereal dermatosis that is considered a premalignant condition by some authors. The clinical manifestations may vary as it evolves through distinct stages, including the initial plaque stage, late tumour stage, verrucous stage, and ultimately transformation into invasive squamous cell carcinoma (SCC).¹ The characteristic presentation includes a well-defined thick hyperkeratotic plaque on the glans with adherent micaceous scaling. The condition, is usually asymptomatic, but may be associated with a burning sensation, fissuring or maceration. Rarely, extensive involvement of the peri-meatal skin, as in our case, may result in multiple streams on micturition, presenting an appearance of a watering-can penis.² Initially, it was considered a benign entity, but later reports have established its progression into verrucous carcinoma.³

Histopathology is diagnostic in most cases showing acanthosis, hyperkeratosis, and pseudoepitheliomatous hyperplasia with no cytological atypia or koilocytes.¹ The atypia may become evident upon malignant transformation. The close differentials of PKMB include Buschke-Lowenstein tumour and verrucous squamous cell carcinoma [Table 1].

Buschke-Lowenstein (BL) tumour, also known as giant condyloma acuminata, is a slow-growing anogenital tumour with a propensity for local invasion. It starts as a keratotic plaque on the glans or foreskin and gradually transforms over the years into a large verrucous or cauliflower-shaped tumour. Human Papillomavirus (HPV) types 6 and 11 are the most commonly implicated. Dermoscopy reveals multiple finger/knob-like projections of varying lengths fusing at their bases and dilated linear vessels haemorrhaging at their tips.⁴ HPE demonstrates papillomatosis with fibrovascular cores and prominent koilocytosis.⁵ In this case, PCR analysis was negative for HPV and HPE failed to demonstrate koilocytes, thereby ruling out BL tumour.

Verrucous carcinoma (VC) is a low-grade, well-differentiated squamous cell carcinoma. It usually presents as a slow-growing warty plaque on anogenital mucosa and has a predilection for local invasion. Dermoscopy is conspicuous demonstrating keratinisation with white to yellow structureless areas, white clods, and circles in addition to polymorphous vessels (looped or glomerular).⁶ HPE is diagnostic, showing prominent hyperkeratosis, broad and blunted rete ridges with thin fibrovascular cores, pushing margins, well-differentiated tumour cells, and foci of keratinisation interspersed with basal cell atypia.⁷ Both atypia and focal keratinisation were absent in our case, even on repeated biopsies. PKMB is a rare entity and should always be considered as a differential for verrucous penile growths. In the absence of malignant changes, the treatment is typically conservative, with options like topical 5-Fluorouracil (5-FU), cryotherapy and radiotherapy.² Local excision becomes necessary when cellular atypia or frank malignant changes are evident. In our case, initial application of 5-FU for 3-4 months yielded minimal improvement. Subsequently, owing to increasing difficulties in micturition, a partial penectomy was performed. It is crucial to follow-up on all PKMB cases, regardless of their treatment statuses, to monitor for recurrence or malignant transformation.