Anti-CD68 monoclonal antibody, clone LQ2 [R-PE]

Background: Erdheim-Chester disease (ECD) is a rare, sporadic, systemic histiocytic disease of unknown etiology with poor therapeutic response. Histologically it is a non-Langerhans cell histiocytosis. Although few cases have been reported in the literature, the incidence has increased in the last 10 years. Case description: A 58-year-old male patient with a newly onset and progressive headache with excessive sleepiness during the last 3 days before its admission. On brain computed tomography (CT) in admission showed two expansive intracranial heterogeneous lesions, one in the posterior fossa on the left cerebellar hemisphere and other over the sellar region both causing obstructive hydrocephalus. A ventriculostomy with peritoneal drainage was performed within hours and after that a good clinical response with complete recovery of the consciousness level was observed. The patient reported that in 2016 he was investigated and diagnosed with an expansive lesion over the sellar area and a microsurgical biopsy was performed. The histopathological exam revealed a chronic lympho-histiocytic inflammatory process with xanthomatous histiocytes infiltration overlying the cerebral parenchyma suggesting the diagnostic of non-Langerhans histiocytosis or Erdheim-Chester disease. Subsequently the immunohistochemical study evidenced CD68 positivity and absent of CD1a and S-100 protein, pattern consistent with the hypothesis suggested by the histopathology exam. After clinical discussions with the neurosurgical and neurological team, the patient proceed with ambulatorial multidisciplinary treatment and follow-up. Conclusions: ECD is a rare pathology, requiring a multidisciplinary approach to diagnosis and treatment.

Intralymphatic histiocytosis is a rare reactive skin condition characterized by a nonspecific clinical presentation and, microscopically, by the collections of mononuclear histiocytes within the lumina of dilated lymphatic vessels. We report a rare case of intralymphatic histiocytosis associated with rosacea and prominent periocular edema (Morbihan disease). The patient is a 56-year-old woman with a 12-year history of rosacea who suddenly developed edema of the right upper eyelid that persisted 6 months before she sought medical advice. Because of an unclear clinical diagnosis, surgical excision of the edematous upper eyelid was performed. The histologic slides showed interstitial edema of the dermis with dilated vascular channels and small epithelioid cell granulomas around hair follicles. In addition, there were aggregates of cells inside numerous lymphatic vessels that were immunohistochemically positive for CD45, CD4, CD68, CD163, CD64, CD14, CD11c, and lysozyme and negative for CD3, CD20, CD30, CD56, S100, CD1a, and langerin.