Asymptomatic scrotal lesions

Case #1: Molluscum contagiosumAlthough somewhat uncommon on the scrotum, molluscum contagiosum (MC) is far from unknown in this area where, especially in young adults, it is considered to be sexually transmitted. The appearance of these smooth, firm, and centrally umbilicated...

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Case #1: Molluscum contagiosum

Although somewhat uncommon on the scrotum, molluscum contagiosum (MC) is far from unknown in this area where, especially in young adults, it is considered to be sexually transmitted. The appearance of these smooth, firm, and centrally umbilicated papules is all but pathognomic for MC, which is caused by a member of the Poxviridae family.¹

The condition was first described by Bateman in 1817, but the contagious nature of the lesions was first described by Paterson in 1841. Worldwide, the incidence appears to be steadily increasing, currently accounting for approximately 1% of all skin disorders diagnosed.²

The MC virus (MCV) only affects the epidermal layer, gaining access through minimal disruptions in the skin, eventuating in a firm, glassy, papule marked by a central caseous plug. The caseous plug is the result of the central accumulation of large hyaline bodies (molluscum bodies), which can be seen microscopically. The molluscum bodies account for the telltale umbilication, which can be highlighted by application of liquid nitrogen.

Although MCV cannot be grown in cultures, restrictive endonuclear analysis of the viral genomic material has allowed the delineation of four types of the virus. MCV type I has proven to be the cause in more than 96% of clinical lesions; MCV type II is the culprit in 60% of MC cases in HIV patients; and MCV types III and IV are rare. No difference has been seen between the severity, morphology, or anatomic distribution of the lesions associated with each MCV type.³

Only slightly smaller than the smallest bacteria, MCV is one of the largest known viruses. The virus is thought to spread through direct contact with persons with MC and objects contaminated by persons with MC. There appears to be an association between MC and the use of swimming pools and participation in school athletics, particularly among boys. Susceptibility is increased markedly in children with atopic dermatitis, whose eczema is often worsened by the presence of mollusca.⁴

MC in the genital area of young, immunocompetent adults can be considered a sexually transmitted disease (STD). Another clinical form of MC has been noted in immunocompromised adults and children, especially those positive for HIV, but also in those being treated with such medications as methotrexate (Rheumatrex, Trexall) and prednisone and the antirejection medications used in transplant patients.

Typical incubation time for MC is two to seven weeks, but as much as six months’ latency has been described.⁵

The classic papules of MC are subject to autoinoculation and tend to form in linear patterns along lines of trauma. These lines of trauma can be accidental or caused by scratching, particularly in young children. Strictly speaking, this is not a true isomorphic response (i.e., the Koebner response) since this phenomenon only applies to such conditions as lichen planus or psoriasis, in which the cause is unknown.

Occasionally, lesions will progress beyond local proliferation and become inflamed. In a fair imitation of bacterial infection, edema, erythema, and increased vascularity are caused by an infiltration of neutrophils, lymphocytes, and monocytes. These lesions almost invariably resolve without treatment, as do most MC lesions. Resolution can be frustratingly slow, however, varying from two months to as long as five years. This lengthy resolution is why one of the mainstays of treatment for this benign but vexing condition is patient/parent reassurance.

The diagnosis of MC is usually straightforward; however, the lesions can be so small as to resemble a rash. MC that coexists with eczema can be difficult to diagnose unless the clinician remembers that these two conditions are frequent traveling companions, especially on the arms. Small, flat warts and lichen planus can do a fair imitation of MC, but more often than not, the elicitation of the umbilication with light application of liquid nitrogen confirms the diagnosis of MC.

No single treatment has proven consistently effective. There is no FDA-approved topical medicine for treatment of molluscum, but existing treatment choices tend to fall into one of four categories.^6,7

Benign neglect. Since MC is self-limited, not harmful, and rarely scars, and because almost all of the various treatments are problematic, patient/parent education is sufficient for many cases.

Direct lesional trauma. Curettage of individual lesions, for example, is highly effective, but may not be practical in younger children or in cases of multiple lesions. The same could be said for application of liquid nitrogen, or such blistering agents as cantharidin.

Antiviral treatment. The use of antiretrovirals in HIV patients with MC can result in improvement in the number and size of the lesions.

Immune-response stimulators. These include topical imiquimod (Aldara, Zyclara), which increases the body’s immune response to viral infection.

Many other types of treatments have been tried, including potassium hydroxide, adhesive tape, dinitrochlorobenzene, squaric acid, and green-tea extract. None of these therapies has been consistently effective, and most have resulted in irritation, blistering, and pain.

The poxvirus responsible for MC is not strongly immunogenic,⁸ but the condition eventually resolves on its own. Complications are few but may include periocular lesions that can trigger a reactionary keratoconjunctivitis. MC lesions confined to the genital areas on young children may necessitate the consideration of possible sexual abuse.⁹

In this case, the patient’s lesions resolved following treatment with liquid nitrogen on three different occasions, each one month apart from the last. Patient education included information regarding potentially more serious STDs. Since the man’s lesions were on the scrotum, where condoms would be useless, he was urged to assume that he was contagious until several disease-free months had passed.

Case #2: Angiokeratoma of Fordyce

John Addison Fordyce, who had seen the lesions on the scrotal floor of a 60-year-old man, first described angiokeratoma of Fordyce (AF) in 1896. Since that time, this condition has been widely recognized as common among older adults. AF can also appear on the labia majora, the inner thigh, the lower abdomen, and, occasionally, on the penile shaft.¹⁰

AF lesions are seldom painful but occasionally bleed. As in this case, the mere discovery of such lesions can cause significant anxiety. Misdiagnosis often leads to overly aggressive treatment, the results of which then become problematic in this sensitive area.^11,12

The soft papules, ranging in size from 1 mm to 3 mm, represent ectatic and thin-walled vessels in the superficial dermis with overlying epidermal hyperplasia.

Angiokeratoma is a broad term, describing various conditions of asymptomatic hyperkeratotic vascular disorders that display a combination of superficial dermal vascular ectasia with overlying epidermal hyperkeratosis on histologic sectioning.¹³ The two forms of angiokeratoma described are localized and systemic.

In addition to AF, other localized forms of angiokeratoma include the solitary papular angiokeratoma (usually located on the leg), a rare and congenital form (angiokeratoma circumscriptum naviforme) with multiple hyperkeratotic papules and plaques appearing unilaterally on the lower extremities and buttocks, and bilateral multiple angiokeratomas appearing on the dorsa of fingers and toes, termed Mibelli type.¹⁰

The most common systemic form of angiokeratoma is angiokeratoma corporis diffusum (ACD), also known as Fabry disease.¹⁴ ACD is a storage disease in which glycosphingolipids accumulate in the skin and viscera, manifesting on the skin and lips as widespread punctate telangiectatic vascular papules that resemble purpura. A few papules will demonstrate hyperkeratotic surfaces. The resulting accumulation of deposits of glycolipids eventually leads to cardiomyopathy, renal failure, and death in the fifth decade. ACD is caused by a deficiency of alpha-galactosidase A and inherited through an X-linked recessive route.

Since the histologic findings are identical for each type of angiokeratoma, localized and systemic forms must be differentiated on clinical grounds. In individuals with Fabry disease, the presence of widespread multiple angiokeratomas, especially on the mucosal surface of the lower lip, can help with diagnosis.

The cause of AF is unknown, but most potential explanations revolve around increases in venous pressure. However, no such connection has been substantiated.¹⁵

No epidemiologic studies of AF have been conducted, but the condition is considered common, particularly among men. Increasing age appears to be a factor, but AF has been reported in children.^11,16

The differential diagnsis for AF includes pyogenic granuloma, squamous cell carcinoma, condyloma, and cherry angioma, among other conditions.

Treatment of AF is seldom necessary. Electrodessication or laser treatment can be used in cases in which the lesion bleeds following trauma.^2,17

The patient described in this case was satisfied with simply knowing the benign nature of the problem and declined any treatment.

Joe Monroe, MD, specializes in dermatology at Dawkins Dermatology in Oklahoma City.