Pseudoepitheliomatous, keratotic, and micaceous balanitis: case report and review of the literature

Dermatology Nursing, April, 2008 by Danielle Perry, Peter J. Lynch, Nasim Fazel

Pseudoepitheliomatous, keratotic, and micaceous balanitis (PKMB) represents an exceedingly rare clinical entity arising on the glans penis in older men. It is an unusual condition about which little is known. This condition most commonly presents as a white, keratofic plaque appearing on the glans penis. PKMB appears to exclusively affect older men, with the mean age at diagnosis being 63 years of age (Bart & Kopf, 1977).

Most cases appear following circumcision late in life. Early biopsy is warranted to differentiate PKMB from other more ominous penile tumors. The course is generally protracted, with many patients failing topical therapy and local excision. Relapse following medical and surgical therapy is not infrequent. In some cases, the condition may progress to verrucous carcinoma or squamous cell carcinoma. These associations warrant close clinical surveillance for malignant transformation.

Case Report

A 52-year-old white male presented to our dermatology clinic with a several month history of penile lesions. Prior treatments included fluocinonide cream, neosporin ointment, and topical anesthetic without improvement. The patient was otherwise healthy and not on any medications. He denied any prior history of genital lesions, and family history was noncontributory. A review of systems failed to reveal any history of fever, chills, pain, or arthritis.

Physical exam revealed a partially circumcised penis with a hyperkeratotic and erythematous plaque with focal erosion covering the entire glans penis (see Figure 1). The penile shaft, scrotum, and inguinal region were otherwise normal. The rest of the physical exam was otherwise unremarkable. Shave biopsy of the lesion revealed confluent parakeratosis, focally increased suprabasilar pleomorphism, and mitotic activity (see Figure 2). Periodic acid Schiff, Steiner, and stain for acid-fast bacilli were all negative. The patient was evaluated by urology staff and revision of circumcision was deferred. He was subsequently treated with clobetasol cream twice daily resulting in substantial improvement after several weeks.

Comment

The first reported cases of PKMB appeared in the French literature in the 1960s (Lortat-Jacob & Civatte, 1961). They described a lesion of the glans penis characterized by thick, hyperkeratotic plaques that spread locally. In 1977, Bart and Kopf reported the first case in the English literature. In this case, as well as a case presented by Read and Abell in 1981, the condition was thought to be of limited malignant potential with a histologically intermediate stage between benign hyperplasia and squamous cell carcinoma (Bart & Kopf, 1977; Read & Abell, 1981). This view was challenged in 1987 when Beljaards, van Dijk, and Hausman reported two cases of PKMB, both of which progressed to verrucous carcinoma with subsequent development of frank squamous cell carcinoma requiring partial penectomy in one case. They argued that the malignant potential of PKMB had previously been underestimated, and believed that the condition should be referred to as micaceous and verrucous malignant balanitis. The most recent literature regards PKMB as a lesion of low-grade malignant potential.

[FIGURE 1 OMITTED]

PKMB is clinically characterized by a white, scaly, keratotic plaque occurring on the glans penis. The term micaceous is applied owing to its resemblance to a naturally occurring silicate of aluminum called mica (Irvine, Anderson, & Pye, 1987). The lesion is usually asymptomatic; however, it can be painful (Ganem, Steele, Creager, & Carson, 1999), and quite disabling when involving the urethral meatus (Zawar, Kirloskar, & Chuh, 2004). The clinical course is generally indolent and protracted, with many patients failing topical therapy and others requiring repeated excisions. In some cases, patients were followed for many years with slow progression of their disease (Read & Abell, 1981).

Although PKMB is considered a unique clinical entity, there is considerable overlap with other penile dystrophies. The differential diagnosis includes squamous cell carcinoma, verrucous carcinoma, keratoacanthoma, giant condyloma, penile horn, and erythroplasia of Queyrat (Read & Abell, 1981). There has been considerable difficulty and controversy in assigning a diagnosis to the histopathology in these cases. For example, Beljaards et al. (1987) argued that the histology of earlier reported cases were consistent with verrucous carcinoma, despite original authors' diagnosis of PKMB. Jenkins and Jakubovic (1988) suggested classifying these lesions as hypertrophic, atrophic, or mixed penile dystrophies, with or without atypia, in a classification system analogous to the classification of vulvar dystrophies proposed by Lavery (Jenkins &Jakubovic, 1988).

[FIGURE 2 OMITTED]

The relationship between PKMB and verrucous carcinoma has been debated with a general agreement that there is considerable overlap between these two clinical entities (Beljaards et al., 1987; Jenkins & Jakubovic, 1988). Verrucous carcinoma is a low-grade squamous cell carcinoma originally described by Ackerman (1948) as an oral tumor with benign histology but locally aggressive behavior. This same tumor was subsequently found to affect nearly every site on the body, including the larynx and genital mucosa (Krans & Perez-Mesa, 1966). Verrucous carcinoma of the penis is generally considered to be synonymous with Buschke-Loewenstein tumor, although not all authors agree (Johnson, Lo, Srigley, & Ayala 1985; McKee, Lowe, & Haigh, 1983; Schwartz, 1990). Verrucous carcinoma is histologically characterized by an exophytic pattern with hyperkeratosis, parakeratosis, and broad, club-shaped rete ridges of well-differentiated squamous epithelium. Anaplasia is generally absent and the granular layer may or may not have vacuolization. There is usually an associated chronic inflammatory infiltrate (Johnson et al., 1985). The morbidity caused by verrucous carcinoma is usually secondary to local infiltration and destruction rather than metastasis. In fact, local lymph node involvement and distant metastases are rare (Johnson et al., 1985; McKee et al., 1983; Schwartz, 1995).