Pityriasis Rotunda: A Dermatophytosis?

To the Editor.— While the basic premise of the study by DiBisceglie et al in the July 1986 issue of theArchives, that pityriasis rotunda may be a paraneoplastic phenomenon, is plausible, there are serious problems with the study and its test data that lead to questioning its validity. 1 The authors suggested that the macular, scaling, arcuate lesions on the torso of ten patients, seven of whom had hepatocellular carcinoma, might be cutaneous markers of their underlying disease, but the suggestion was made without submitting data to show that another source of such lesions, dermatophytosis, was considered in their differential diagnosis. Where are the results of such basic studies as their potassium hydroxide preparations, Sabouraud's fungal cultures, or cutaneous biopsies with periodic acid-Schiff stain and diastase digestion? The published photomicrograph of a cutaneous biopsy specimen is compatible with tinea when only a hematoxylin-eosin stain is used; the legend