Multicentric Reticulohistiocytosis: a Critical Review

Abstract

The literature reports approximately 300 cases of multicentric reticulohistiocytosis (MRH) worldwide, mostly women of Caucasian origin. MRH manifests as a symmetric erosive polyarthritis mimicking rheumatoid arthritis with the subsequent appearance of typical papulonodular skin lesions. The disease may rapidly progress towards mutilans arthritis in the majority of cases, but it generally remits spontaneously in 10 years. The only diagnostic hallmark for MRH is the observation at histology of numerous histiocytes and multinucleated giant cells and ground glass eosinophilic cytoplasm. Despite its rarity, clinical and pathogenetic challenging features characterize the condition. First, the differential diagnosis with other forms of arthritis and the frequent coexistence of neoplasms or autoimmune diseases warrant a careful evaluation of suspected cases. Second, data from isolated MRH cases are consistent in supporting a role for monocyte/macrophage cells and for an enhanced osteoclastic activity in the affected tissues. Third, beside anti-inflammatory treatments, promising reports suggest that biologics targeting TNF-alpha and bisphosphonates may prove beneficial in MRH. Based on these observations, we are convinced that our understanding of this rare condition may prove beneficial in mechanistic advancement for other more prevalent inflammatory conditions such as arthritidies and other bone diseases.

Looks Can Be Deceiving: A Case Report on Multicentric Reticulohistiocytosis Successfully Treated with Rituximab

“…MRH is more common in women with an approximate gender ratio of 3:1. The mean age at diagnosis is usually in the fourth decade of life [2]. Pathogenesis is idiopathic but is associated with elevated levels of cytokines, including tumor necrosis factor (TNF)-alpha and interleukins (IL), such as IL-1B, IL-6, and IL-8, during the active phase of MRH [3].…”

Efficacy of Vinblastine and Prednisone in Multicentric Reticulohistiocytosis With Onset in Infancy

“…[1][2][3] It usually affects individuals in the fourth decade of life and is very rare in children. [2][3][4] To the best of our knowledge, ∼13 pediatric cases have been reported (Table 1), our case being the youngest of all with the earliest presentation at the age of 3 months. 1,5,6 MRH predominately affects female individuals, both in the adult and pediatric populations.…”

“…A similar pattern of clinical presentation is also noticed in pediatric MRH. 2,3 Skin lesions are usually in the form of reddish brown papules and nodules varying in size from a few millimeters to several centimeters, which are usually asymptomatic. Skin ulceration is unusual in MRH 18 ; however, our patient had recurrent ulceration and healing of skin lesions.…”

“…There is no definite treatment protocol for MRH, and various drugs have been attempted with inconsistent results. 1,3 We tried vinblastine and prednisone in this case with good response, which has not been attempted before.…”

“…Characteristic histologic findings include infiltration of histiocytes and multinucleated giant cells with a homogeneous eosinophilic ground glass cytoplasm. [1][2][3][4] Early diagnosis and immediate treatment are important to prevent irreversible joint deformity. There is no definite treatment protocol for MRH, and various drugs have been attempted with inconsistent results.…”