Paraneoplastic pemphigus as a presentation of acute myeloid leukemia: Early diagnosis and remission

Skin lesions are frequently encountered in clinical practice which can be a presentation of systemic diseases not excluding an occult malignancy. Commonly reported paraneoplastic dermatologic manifestations include acanthosis nigricans, dermatomyositis, erythroderma, hypertrophic osteoarthropathy, Sweet syndrome, and paraneoplastic pemphigus (PNP). PNP is a rare autoimmune mucocutaneous disease characterized by severe stomatitis, polymorphic skin eruptions, and associated underlying neoplasms most commonly non-Hodgkin's lymphoma, chronic lymphocytic leukemia, and Castleman disease. PNP is characterized on histopathology as dyskeratotic epithelial cells with acantholysis with a typical immunofluorescence staining pattern of direct and/or indirect staining of intercellular, basement membrane, and dermoepidermal junction with immunoglobulin-G and C3. PNP has been described to have poor prognosis with a mortality range of 75-90% and a mean survival of less than 1year. We describe a previously unreported case of PNP associated with acute myeloid leukemia (AML) where the patient presented with a nonhealing ulcer and hemorrhagic crusting on the face that did not respond to antimicrobials and steroids. Investigations revealed leukocytosis with peripherally circulating blasts. Skin biopsy revealed an evolving PNP and bone marrow biopsy confirmed evidence of AML. The patient underwent induction, consolidation, and then successful allogenic bone marrow transplantation with complete remission. The skin lesion, which was initially refractory to treatments, surprisingly resolved within 7days of starting induction chemotherapy. In this case, the skin lesion was a key factor in early diagnosis and instituting treatment for the underlying AML. Early intervention gave our patient a better outcome with an ongoing survival of 18months since diagnosis, maintaining complete remission.