Malignancy or dermatophyte infection? The challenges in evaluation of chronic diffuse rashes

Introduction: The purpose of our case presentation is to help understand the use of diagnostic studies in differentiating diffuse rashes with potentially underlying malignant etiology from infectious etiology.

A 40 y.o. F with a past medical history significant for anemia presented to the ED with painful rashes that had been getting worse for over 1 year. She mentioned that initially the rash began on her arm around the time when her 2 dogs were being treated for fungal infection and then it started spreading to her chest, back, upper extremities, lower extremities, abdomen, and genital areas as well. She described the rash as flaky and pruritic but denied any associated pain. She admitted to having tried several over-the-counter creams with no improvement. In addition, the patient had recent significant unintentional weight loss.

On physical examination, her skin was noted to have brown plaques and patches with excoriations, flaking, and sharp violaceous borders present on her forehead, neck, chest, abdomen, arms, anterolateral thighs, ankles, and feet. They were non-erythematous and non-blanching. The diffuse nature, persentience, and slow growth of these rashes were concerning for an underlying malignant etiology such as cutaneous T-cell lymphoma (mycosis fungoides or Sezary syndrome), Kaposi’s sarcoma, and erythema gyratum repens secondary to GI/GU malignancy. Another differential considered was immunobullous rash secondary to medication reaction.

Methods: To work-up the top two differentials for this patient which were lymphoma/malignancy-related rash and skin mycosis, extensive diagnostic work up was done. Imaging included CT scans of the chest, pelvis, and abdomen, and pelvic ultrasound. Additional labs were ordered such as beta-D-glucan level, HIV testing, shave biopsy, lymph node excisional biopsy, and zinc levels.

Results: CT of the chest showed enlarged axillary and lateral chest wall lymph nodes. CT of the abdomen and pelvis showed enlarged masslike appearance of the uterus with fluid-filled, displaced endometrial cavity, moderate pelvic ascites, abnormally enlarged inguinal lymph nodes as well as possible retroperitoneal and iliac chain adenopathy. Pelvic U.S. showed enlarged leiomyomatous uterus. Excisional lymph node biopsy did not show presence of malignant cells. Shave biopsy of the rash was negative for fungal stains and showed non-specific dermatitis. Serum beta-D-glucan levels came back significantly elevated at 230 pg/mL (normal range is

Discussion: The challenge in this case was trying to understand the rashes could be of fungal etiology as they don’t tend to be extensive unless the patient is immunocompromised. According to the results, it seems that the patient most likely has a systemic fungal infection as shown by shave biopsy results, elevated beta-D-glucan levels, and lymph node biopsy negative for malignancy. Patient is currently being treated with antifungals. But, we still cannot rule out malignancy until there is improvement with current treatment regimen and mycosis fungoides can be ruled out by outpatient Hem/Onc follow-up.