A poroma is a benign sweat gland tumor composed of cells with terminal ductal differentiation of either apocrine or eccrine origin. Poromas are usually solitary, slow-growing, skin-colored, sometimes pedunculated papules or plaques. Multiple poromas, or eccrine poromatosis, rarely develop in a widespread distribution: 2 cases of eccrine poromatosis have been reported in the setting of chronic immunosuppression1,2; 3 additional reports document the development of multiple eccrine poromas after external irradiation.3-5
Our patient developed multiple eccrine poromas after treatment with an allogeneic stem cell transplant with complications of graft-vs-host disease (GVHD) requiring long-term immunosuppression. The poromas were tested for human papillomavirus (HPV) DNA by nested polymerase chain reaction (PCR), and results were positive for beta-HPV. An actinic keratosis and a squamous cell carcinoma (SCC) in situ tested by nested PCR were negative for beta-HPV. To our knowledge, this is the first reported case of HPV positivity in eccrine poromas.
Our patient was a 53-year-old man with a history of mantle cell lymphoma who was treated with an allogeneic stem cell transplant. Over the next 5 years, his posttransplantation course was complicated by chronic GVHD of the skin, mouth, eyes, liver, and gastrointestinal tract, which was managed with photopheresis and immunosuppression with tacrolimus, systemic corticosteroids, and mycophenolate mofetil. He subsequently developed 6 slow-growing, erythematous papules on his palms, heels, and left elbow (Figure 1). The papules ranged in size from 2 to 6 mm, and all were similar in morphologic characteristics except for the pedunculated papule on the elbow.
Biopsy specimens of the right palm, elbow, and left heel demonstrated dome-shaped epidermal proliferations composed of small, cuboidal (“poroid”) cells with basophilic nuclei emanating from the base of the epidermis and extending into the dermis, which are findings characteristic of eccrine poromas (Figure 2). Findings of in situ hybridization studies for low-risk and high-risk alpha-HPV types were negative; however, nested PCR findings for beta-HPV or epidermodysplasia verruciformis (EV) HPV DNA were positive for HPV types 20, 21, and 23 (Figure 3).
Our patient developed severe multisystem GVHD and multiple HPV-positive eccrine poromas after several years of immunosuppressive therapy, which is the third report to our knowledge of multiple eccrine poromas developing in an immunosuppressed patient. Although we have not found HPV positivity reported in any cases of eccrine poromas, 1 study using immunoper oxidase techniques and bovine papillomavirus type 1 to test poromas reported a negative result for HPV.6
Human papillomaviruses are double-stranded DNA viruses confined to epithelial cells of the skin and mucous membranes of humans. Isolates from the beta-HPV genus exist in latent form in the general population and are activated under conditions of immune suppression. Our patient's lesions tested positive for beta-HPV types 20, 21, and 23, which cause mostly benign cutaneous lesions and are commonly associated with lesions in EV or immunosuppression. Transplant patients are more prone to persistent cutaneous HPV infection, and so in our patient, a combination of long-term immunosuppressive therapy and HPV infection may have collectively contributed to the development of multiple poromas. Beta-HPV was not detected in an actinic keratosis and SCC in situ of the perilesional skin, which is compatible with evidence that beta-HPV may not be merely a “passenger” but rather may play an active role in poroma tumorigenesis. It is interesting to postulate that HPV may have induced the development of multiple poromas. The presence of HPV DNA in the poroma biopsy specimens, however, does not definitively establish a direct causal role. More studies are needed to investigate the molecular mechanism by which HPV infection impacts poroma tumorigenesis.
Correspondence: Dr Diamantis, The University of Texas Southwestern, Austin, PO Box 341752, Austin, TX 78734 (firstname.lastname@example.org).
Accepted for Publication: June 4, 2010.
Author Contributions: All authors had full access to all the data in the study and take responsibility for the integrity of the data and accuracy of the data analysis. Study concept and design: Diamantis, Richmond, Tyring, and Hymes. Acquisition of data: Diamantis, Richmond, Rady, Tyring, Cutlan, Torres-Cabala, and Hymes. Analysis and interpretation of data: Diamantis, Rady, Tyring, Torres-Cabala, and Hymes. Drafting of the manuscript: Diamantis, Torres-Cabala, and Hymes. Critical revision of the manuscript for important intellectual content: Diamantis, Richmond, Rady, Tyring, Cutlan, Torres-Cabala, and Hymes. Statistical analysis: Diamantis. Administrative, technical, and material support: Diamantis, Rady, Tyring, Cutlan, and Torres-Cabala. Study supervision: Diamantis, Richmond, Tyring, and Hymes.
Financial Disclosure: None reported.
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