In the latest Clinical Problem-Solving article, a 67-year-old man with hairy-cell leukemia presented to the clinic after 3 days of fevers, night sweats, arthralgias, and an erythematous vesicular-appearing rash on his back. He had not had headache, shortness of breath, bleeding episodes, vomiting, or diarrhea.
When caring for an immunocompromised patient, the clinician must continually reevaluate the differential diagnosis if the patient has not had the expected response to therapy, bearing in mind that multiple, concurrent disease processes may be present.
•What type of lymphocyte is primarily affected in hairy cell leukemia?
Hairy-cell leukemia is primarily a disorder of B cells, although T cells are also impaired.
•What type of hematologic neoplasm is most commonly associated with a neutrophilic dermatosis?
A neutrophilic dermatosis can be seen with virtually any type of hematologic neoplasm, although it is most often associated with acute myeloid leukemia.
Morning Report Questions
Q: What is Sweet’s syndrome?
A: Sweet’s syndrome is an acute, febrile, neutrophilic dermatosis that can be associated with drugs, infection, inflammatory bowel disease, pregnancy, cancer, and many other illnesses. The syndrome is characterized by painful inflammatory nodules, papules, and plaques and is often accompanied by malaise, arthralgias, myalgias, and headaches. Dermal edema may lead to a pseudovesicular pattern. The pathogenesis of Sweet’s syndrome is not well understood, but it may be a hypersensitivity reaction in which the body’s response to an infection, cancer, or other illness stimulates the production of cytokines, including granulocyte colony-stimulating factor. This process eventually activates neutrophils and promotes abnormal migration of these neutrophils into dermal tissues.
Figure 1. Rash on the Patient’s Back at Presentation.
Q: How is Sweet’s syndrome diagnosed?
A: A commonly used diagnostic algorithm for Sweet’s syndrome requires confirmation of two major criteria and at least two of four minor criteria. The major criteria are the abrupt onset of painful or tender erythematous plaques or nodules and histologic findings that reveal a dense neutrophilic infiltration in the dermis without leukocytoclastic vasculitis. The minor criteria are malaise and fever, with a temperature higher than 100.4 degrees F (38 degrees C); association with an underlying cancer, inflammatory disease, pregnancy, vaccine administration, or nonspecific infection; substantial response to treatment with systemic glucocorticoids or second-line agents such as dapsone, colchicine, or potassium iodide; and three of the following abnormal laboratory values: erythrocyte sedimentation rate greater than 20 mm per hour, an elevated level of C-reactive protein, leukocytosis in which the white-cell count is greater than 8000 per cubic millimeter, and a percentage of neutrophils in the differential count that is greater than 70% as determined on a peripheral-blood smear.
Figure 3. Skin Biopsy.