CASE REPORT
A 6-year-old boy with Neurofibromatosis type-1 (NF-1), presented with symptoms of progressive pallor, fever and muco-cutaneous bleeding. He was diagnosed to have acute myeloid leukaemia (AML) after bone marrow aspiration, flow cytometry based immunophenotyping and cytogenetic evaluation. The patient was treated with standard multidrug intensive chemotherapy (MRC-15 AML Protocol3), following which the child was in remission. Both the parents had genetic disease, NF1 in father and skeletal dysplasia (hereditary multiple exostosis) in mother.
Sixteen months from initial diagnosis, the child presented with prolonged fever and diffuse erythematous papules distributed over arms, legs, face, trunk and neck. Investigations revealed leucocytosis, thrombocytopenia and circulating blasts in peripheral smear. A bone marrow aspiration and biopsy confirmed relapse of the AML with the immunophenotype and cytogenetics similar to the primary disease. The child was hence planned for salvage chemotherapy followed by consolidation with hematopoietic stem cell transplantation (HSCT). The skin lesions were assumed to be leukemic deposits and hence were not biopsied upfront for histological evaluation.
The child received first cycle of chemotherapy (Azacytidine based), following which there was clinical improvement in terms of disappearance of circulating blasts and defervescence of fever. Contrary to the clinical expectation, the skin lesions however, continued to progress with crops of blotchy papules with increased tenderness (Fig 1A). A biopsy of the skin lesion was hence pursued which showed dense neutrophilic infiltration in the dermis suggestive of acute neutrophilic dermatosis also termed, Sweet’s syndrome (Fig 1B). The patient was initiated on oral steroids (prednisolone 2mg/kg for a week followed by tapering doses over next 2 weeks) following which there was remarkable response. After 2 weeks, on tapering steroids, there was recurrence or flare of skin lesions. Oral colchicine was hence added as a steroid sparing agent following which there was complete response. The steroids could be tapered and stopped in next 1 week. Oral colchicine was used for a total of 4 weeks. The child received 3 cycles of salvage chemotherapy (Azacytidine followed by Fludarabine and high dose cytarabine) following which the disease was in morphological remission (minimal residual disease 1.7%). He underwent a haplo-identical stem cell transplantation with mother as the stem cell donor. He remains disease free and well at 24 months from HSCT.