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case_images: (A-C) Skin condition before and after treatment. Upon admission, multiple yellowish-red or reddish-brown papules and nodules almost spread throughout the body, with clear boundaries and partial fusion. The back area was the most severe (A). After the completion of 4 courses of CHOP+ lenalidomide, the rash subsided significantly, with significant pigmentation on the back (B). Two courses of chemotherapy were completed after recurrence, and the rash almost completely subsided with only a small amount of pigmentation on the back (red arrow, biopsy scar after recurrence) (C). (D) [18F] FDG-PET/CT showed considerable metabolic increases in the skin (the red arrows point to some areas exhibiting heightened metabolic activity). Areas including the upper limbs (upper arm), lower neck, body (back), and the skin/subcutaneous area of the upper thighs of both sides within the detection range, and some of them were accompanied by small nodular shadows. The possibility of malignant tumor lesions was considered. Immunohistochemical studies demonstrated that the histiocytes were positive for CD1a (E), CD68 (F) and S-100 (G) and negative for Langerin (H).
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case_images: The papules started on the left forearm without pain, ululation, and purulent discharge and then gradually spread to the trunk, extremities, face, and scalp (Figure 1). To exclude other malignant tumors, the patient underwent PET-CT (Figure 1), and the possibility of malignant tumor lesions was considered. Until May 2022, when the rash recurred, the skin biopsy of the back lesion was performed again, and the immunochemistry revealed no significant changes except for S100 compared with the previous one (Figure 1).
case_images: The timeline of this case report.
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case_images: Figure 2 shows the timeline of our case.