Papulonodular mucinosis: a systematic review on clinicopathologic characteristics, course and treatment options.

Papulonodular mucinosis (PNM) is a rare cutaneous mucinosis recognized as a rare variant of lupus erythematosus. There are no large-scale cohort studies characterizing its clinicopathological features or evaluating the effectiveness of various treatment options. This study aimed to review the literature on PNMs to identify its clinical and histological features and treatment outcomes. The search includes studies from the PubMed, Embase, and Cochrane Library databases up to the March 1, 2024. A total of 37 studies, encompassing 44 patients, were included in the review. Of these, 20 were males and 24 females, with a mean age at diagnosis of 34.9 ± 1.92 years. PNM lesions are characterized by generalized papules, plaques, and nodules, and histopathologically, they show abundant mucin deposition throughout the dermis. The temporal relationship between PNM and SLE is variable. There is no evidence that SLE patients with PNM are more prone to organ involvement or increased disease activity. A combination of medical history, clinical features, and histopathological findings is essential for diagnosis; however, misdiagnosis is possible until lupus erythematosus (LE) becomes evident. Hydroxychloroquine and systemic glucocorticoids are the current mainstays of treatment for PNM, with most patients achieving partial or complete remission.