Rossi-Dorfman Disease (RDD), or Sinus Histiocytosis with Massive Lymphadenopathy (SHML), is a rare benign disease of unknown etiology and self-limited character that typically presents as painless cervical lymphadenopathy and fever. To report a case of RDD with isolated involvement of the fifth lumbar vertebra.

A 27-year-old male patient was admitted to the medical clinic with low back pain for six months, evolving with plegia of the lower limbs. Magnetic resonance imaging showed a collapse of the fifth lumbar vertebra, with a 50% reduction in height, associating the heterogeneity of the remaining bone matrix with an infiltrative pattern and posterior retropulsion promoting obliteration of the L5-S1 right lateral process. Surgical decompression and L5 arthrodesis were performed. The bone matter was sent for histopathological evaluation and immunohistochemical profile, revealing CD68+, S100+ and Vimentin+, aspects compatible with DRR. Laboratory tests were within normal limits. Chest and abdominal computed tomography did not reveal lymph node enlargement. It was decided to carry out 25 adjuvant radiotherapy sessions for local control and prevention of possible recurrences.

RDD is a disease belonging to the group of primary histiocytosis histologically defined by the phenomenon of emperipolesis, engulfment of intact lymphocytes or plasma cells in the cytoplasm of histiocytes or giant cells. While the etiology remains unknown, infectious and autoimmune mechanisms are suspected to be involved. The natural history of the disease has a benign and self-limited course; in 70% of patients, the disease is permanent and stable, 20% have spontaneous remission, and 10% progress to generalization. It mainly affects children and young adults, the mean age being 19-year-olds, with a slight predilection for males. The clinical presentation is dependent on the location and size of the lesions. The involvement is classically confined to lymph nodes, however, in 23% of cases, the pathology can be present in extra-lymph node sites, such as skin, soft tissues, nasal cavity, paranasal sinuses, eye sockets, bones, salivary glands and the central nervous system. Of these cases, only 11% have presentation in the bones. Laboratory tests commonly show polyclonal hypergammaglobulinemia, increased red cell segmentation index, and anemia. Histopathological examination with immunohistochemical technique is essential to confirm the diagnosis. Treatments include steroids, chemotherapy and radiotherapy.

RDD is a rare benign disease whose symptoms stem from the location and size of the neoplastic growth which can produce a variety of clinical syndromes. Without recognition and proper management, the disease is a diagnostic challenge that can evolve unfavorably.