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13-year-old girl with agminated papules on back
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A 13-year-old Hispanic female presented to the pediatric dermatology clinic for evaluation of “large bumps” on her back. She was diagnosed with anterior uveitis 2 years ago and has been followed by both ophthalmology and rheumatology clinics. She has been treated during the past several years with methotrexate and mycophenolate mofetil; most recently, she had Remicade infusions added to her regimen.
The lesions on her back appeared soon after initiating treatment with mycophenolate mofetil; however, since beginning her Remicade (infliximab, Janssen Biotech) infusions, the bumps have significantly increased in size and number. The bumps do not hurt or itch. She has not traveled outside the state in the past year, and she has not spent time hiking or vacationing in the nearby deserts.
Image: Krakowski AC
On exam, the patient is a healthy-appearing teenager with flesh-to-pink colored, agminated (ie, clustered) papules on the right flank. The papules range in size from 3 mm to 2 cm, with several of them appearing to be umbilicated. They do not cross the midline, and they do not appear to be dermatomal.
The lesions possess a somewhat-firm, rubbery texture but do not invaginate into the skin with pressure (Figure 1). She has no café au lait macules, axillary or inguinal freckling, or Lisch nodules. She does not have a cough or shortness of breath.
Case Discussion
Answer: Molluscum contagiosum (D)
The differential diagnosis for these lesions could include neurofibromas based on the size and rubbery texture of the patient’s papules. However, this diagnosis is unlikely given the lack of any other signs or symptoms of neurofibromatosis and the fact that these lesions did not “button-hole” — invaginate into the skin with pressure — a physical exam sign often associated with true neurofibromas.
Due to the patient’s state of long-term immunosuppression, ruling out an underlying fungal infection — including Cryptococcus, histoplasmosis and coccidioidomycosis — was the primary concern. A biopsy for hematoxylin and eosin staining and tissue culture was performed. Histopathology revealed inverted lobules of squamous epithelium with numerous cells showing eosinophilic glassy cytoplasmic inclusions within the stratum spinosum, extending into the stratum corneum as well as at the skin surface. These findings are consistent with infection by molluscum contagiosum. Fortunately, her tissue culture, which was held for 12 weeks, also returned “negative” for any evidence of bacterial or fungal infection.
Molluscum contagiosum is a pox virus that is responsible for producing molluscum lesions in the skin of susceptible individuals. In its typical presentation, molluscum infection results in small (1 mm - 4 mm), flesh-to-pink colored papules, often with a central umbilication and central whitish core. The “giant” lesions observed in this patient are relatively uncommon and have been reported in the literature as being associated with HIV infection. However, patients on T-cell immunosuppression, such as renal transplant patients, also have been reported to manifest giant molluscum that are often difficult to treat. It may be that our patient’s immunosuppression, especially the recent addition of infliximab, spurred viral growth.
Because of the size of the lesions and the patient’s inability to mount a normal immunological response, several “traditional” molluscum contagiosum treatments, including cantharidin, oral cimetidine and cryotherapy, were abandoned. Instead, she opted to have the lesions removed by shave excision. She has since healed without any adverse effects, and she remains on her immunosuppressive regimen without signs of new lesions.
- References:
- Chatterjee S, et al. Trop Doct. 2015;doi:10.1177/0049475514568133.
- Chen X, et al. Lancet Infect Dis. 2013;doi:10.1016/S1473-3099(13)70109-9.
- Piaserico S, et al. G Ital Dermatol Venereol. 2014;149:409-415.
- For more information:
- Emily Osier, MD, is a clinical research fellow in pediatric dermatology at Rady Children’s Hospital, San Diego. She can be reached at 8010 Frost St., Suite 602, San Diego, CA 92123; email: ejosier@gmail.com.
- Andrew C. Krakowski, MD, is an attending physician at Rady Children’s Hospital, San Diego.
Disclosures: Osier and Krakowski report no relevant financial disclosures.