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Hypopigmented disorder diagnosed as member of parapsoriasis family

An uncommon hypopigmented disorder was diagnosed as hypopigmented parapsoriasis en plaque, according to study results.

Researchers in Cairo, Egypt, studied 34 patients (mean age, 27.1 years; 64.7% male) who had presented with an unusual hypopigmented disorder (mean disease duration, 15.32 months) between May 2003 and February 2010. A predesigned algorithm was performed to exclude all possible differential diagnoses of hypopigmented lesions.

Thirty-one patients completed the study. Patients maintained narrowband ultraviolet B phototherapy three times a week.

Researchers said the following findings dictated a diagnosis of hypopigmented parapsoriasis en plaque (PSEP):

• other disorders causing similar hypopigmented lesions were excluded
• shape (multiple oval to round persistent and/or progressive hypopigmented patches) and lesion size (small macules less than 2 cm in 73.5% of patients and large patches of at least 6 cm in the longest axis in 26.5% of patients) resembled classic small PSEP
• lesion distribution on the trunk, proximal upper and lower limbs was similar to classic small PSEP
• 70.5% of patients had digitform extension of most lesions as in small PSEP
• an absence of itching as in PSEP (small-plaque parapsoriasis type)
• 76.4% of patients displayed complete clearance of lesions after phototherapy
• during up to 2 years of follow-up, 14.7% of patients converted into hypopigmented mycosis fungoides (MF)

Researchers said limited resources prevented the performing of clonal T-cell receptor gene rearrangement.

“We believe that hypopigmented PSEP is a well-defined new variant of the PSEP family that shows, apart from hypopigmentation, all the features of PSEP, particularly the small PSEP variant,” the researchers concluded. “Moreover, as small PSEP, it can progress to MF. Awareness of this entity is required especially when evaluating patients with idiopathic hypopigmented macular lesions, bearing in mind that these patients require biopsy and follow-up to evaluate for possible evolution to MF.”