Hyperpigmented patches on the back: a clinicopathological study from Iran

The description on patients with pigmented back patches is rarely reported in the literature. We decided to study the clinicopathological aspects of these patients for reaching a better understanding of this disease. In this study, the clinicopathological aspects and probable responsible factors in the manifestation of posterior pruritic pigmented patches in patients referred to the dermatology clinic of Qaem University Hospital from October 2007 to September 2009 were surveyed. All 60 patients who were enrolled in our study were female with a mean age of 31.43±9.71 years. Six patients did not consent to biopsy. The most common finding in pathological examination of the skin samples of the 54 patients was the presence of melanophage in the dermis in 100% of them. After considering all findings in the medical history, physical examination and histopathological studies, the final diagnosis was as follows: macular amyloidosis in 26 (48.15%), post-inflammatory hyperpigmentation in 14 (25.93%), rubbing melanosis in 9 (16.67%), notalgia paresthetica in 3 (5.55%), and papular amyloidosis in 2 (3.10%) patients. According to our results, the most common causes of posterior pruritic pigmented back patches are macular amyloidosis and post-inflammatory hyperpigmentation.