Case Presentation: A 62-year-old man with a history of hypertension, hyperlipidemia, and melanoma presented to our tertiary care hospital from an outside institution with 3-4 weeks of rapidly progressive skin nodules, a 10 pound weight loss, and diffuse joint aches. The nodules were of varying sizes, first appearing along his clavicle and progressively spreading throughout his entire body. He had migratory pain in the large joints of his upper and lower extremities, limiting his ability to walk independently. A previous biopsy of the initial skin lesion was negative for pathology. On arrival to the hospital, he had an increasing oxygen requirement to 2 liters of oxygen via nasal cannula to maintain oxygen saturations above 90%. He was hypotensive with a blood pressure of 94/50 and afebrile with a temperature of 99.2F. He presented with a normocytic anemia with a hemoglobin of 10.6 and thrombocytopenia with a platelet count of 79. Physical exam revealed several hemorrhagic and flesh-colored nodules of varying sizes, measuring between 2 and 12 cm on his face, trunk, extremities and genitalia. The nodules were nontender, nonpurulent, and nonpruritic. The testicles were enlarged to 9cm. He had nontender lymphadenopathy of the bilateral cervical chains, edema in bilateral upper extremities, most prominently in his wrists, sinus congestion, and dry mucous membranes.Deep shave biopsy was positive for CD33+ infiltrate, consistent with the reactive T-lymphocyte infiltrate seen in leukemia cutis. Peripheral blood cytometry detected 22% blasts and bone marrow biopsy confirmed 63% blasts in hypercellular marrow. A gene panel demonstrated three copies of RUNX1T1, suggesting trisomy 8. Acute myeloid leukemia with concurrent leukemia cutis was diagnosed in the patient and he was started on standard induction chemotherapy with idarubicin and cytarabine.
Discussion: Leukemia cutis is a cutaneous manifestation of both myeloid and lymphoid leukemias secondary to neoplastic infiltration of the skin. It is a rare precedent of acute myeloid leukemia and can be a clinically challenging diagnosis when these skin infiltrates precede bone marrow changes or an existing diagnosis of leukemia.
Conclusions: This case demonstrates that leukemia can initially manifest as subcutaneous nodules, despite a negative initial biopsy. Although most cases of leukemia cutis occur after a diagnosis of systemic leukemia has been established, this case demonstrates the possibility of a concomitant diagnosis of leukemia cutis with a systemic leukemia, often heralding a poor prognosis.