Multiple Reticulohistiocytomas in an 88-year-old Man: a Case Report

Solitary and multiple reticulohistiocytomas, often referred to as diffuse cutaneous reticulohistiocytosis, that are generally restricted to skin, must be differentiated from multicentric reticulohistiocytosis. Multicentric reticulohistiocytosis is a rare histiocytic proliferative disease affecting joints, skin and mucous membranes, while arthropathy usually precedes skin and mucosal involvement. Other organs may also be involved, and 20% of patients have an associated internal malignancy. Multicentric reticulohistiocytosis has been reported to be associated with autoimmune diseases and malignancies. We present an 88-year-old man, with a sudden eruption of asymptomatic, firm, skin to brown colored papules and nodules, 6 to 17 mm in diameter, localized on forehead, arms, legs, and buttocks. There were no symptoms of joint or other organ involvement. Clinical and dermoscopic characteristics pointed to reticulohystiocytomas. Multiple excision biopsies of different tumors were performed and histopathology reports confirmed the diagnosis. In the case presented, reticulohistiocytosis was limited to the skin, exhibiting multiple reticlohistiocytomas with typical clinical, dermoscopic and rather peculiar histopathology presentation. Apart from this, some histologic features were seen in early lesions of multicentric reticulohistiocytosis, such as multinuclear cells dissociating collagen fibers with pale eosinophilic and foamy cytoplasm. Besides surgical excisions, no other treatment options were done. Laboratory and other tests showed no presence of extracutaneous illness, and no autoimmune or paraneoplastic processes. At one year follow up, the remaining tumors were of the same size, but there were no recurrences at excision sites, no signs of disease progression or systemic involvement. Since diffuse cutaneous reticulohistiocytosis without arthropathy as well as isolated reticulohistiocytomas have been described, in some cases of multiple reticulohistiocytomas even without systemic symptoms and signs, multicentric reticulohistiocytosis should be considered with an appropriate follow up. In such cases, skin lesions have the same histological features as lesions in multicentric reticulohistiocytosis, but they are not associated with joint problems or neoplasms.