Pure Cutaneous Rosai Dorfman Disease: An Uncommon Location for a Rare Histiocytic Proliferative Disorder.

RosaiDorfman disease (RDD) is a rare, self-limiting disease of uncertain etiology involving lymph nodes as well as extranodal sites. Isolated or pure cutaneous RDD (PCRDD) without lymph node involvement is very unusual accounting for only 3% of all described cases of RDD. The clinical features of PCRDD are quite different from RDD according to the literature on extranodal RDD, thereby emphasizing that PCRDD is a distinct clinical entity. Histopathology remains the gold standard for the diagnosis of both systemic and PCRDD with the presence of characteristic emperipolesis observed in histiocytes while immunohistochemistry (IHC) (S100, CD 68 positive, and CD 1a-negative) serves as a useful adjunct. We hereby report a case of a 36-year-old female who presented with a tender, indurated plaque on the left forearm with a clinical differential diagnosis of borderline tuberculoid leprosy/sarcoidosis and lupus vulgaris. However, on histopathology, a diagnosis of RDD was performed and confirmed on IHC. This case highlights the need to create awareness among young pathologists and clinicians about PCRDD to prevent overzealous treatment.

Jain M ，Pujani M ，Sidam D ，Wadhwa R ，Passi S ，Uikey D ... -  《-》

Diagnostic consideration of lipoma-like lesion: A case report of primary cutaneous Rosai-Dorfman disease.

Rosai-Dorfman disease (RDD) is a rare disorder characterized by benign histiocytic proliferation. The purely cutaneous variant of Rosai-Dorfman disease is exceptionally uncommon. This abstract centers on an extraordinary case-an instance of primary cutaneous Rosai-Dorfman disease (PCRDD), a rare cutaneous variant within an already infrequent disorder. Successfully managed through surgical intervention, this unique case underscores the pressing need for refined diagnostic and therapeutic strategies. We present a noteworthy case of primary cutaneous Rosai-Dorfman disease (PCRDD) in a north African female, deviating from the typical age of onset. The patient exhibited a rare cutaneous variant, emphasizing the need for heightened awareness in diverse demographics. Histological analysis revealed characteristic emperipolesis and immunohistochemical features consistent with RDD. PCRDD, although uncommon within the Rosai-Dorfman Disease spectrum, manifests with a later onset and distinctive demographic characteristics. Surgical excision emerges as a viable therapeutic option for managing symptomatic lesions, as demonstrated in our case. The infrequency of PCRDD underscores the importance of tailored diagnostic and therapeutic strategies. Individualized approaches become pivotal in addressing the complexities associated with PCRDD, ensuring careful consideration of its intricacies in the broader context of Rosai-Dorfman disease. This case underscores the complexity of RDD, especially in rare cutaneous presentations. Surgical excision, with its reported efficacy, stands as a crucial intervention, offering both symptomatic relief and potential cure, showcasing the significance of individualized care in managing this rare disorder. Continued research remains imperative for advancing RDD understanding and refining clinical approaches.

Touati MD ，Omry A ，Ferjaoui W ，Haloui N ，Gargouri F ，Khalifa MB ... -  《International Journal of Surgery Case Reports》

A Case of Rosai-Dorfman Disease Presenting as an Isolated Pleural Plaque.

Rosai-Dorfman disease (RDD) is a rare non-Langerhans histiocytic disorder primarily involving lymph nodes. Extranodal RDD has a heterogenous presentation, and isolated pulmonary involvement is rare. We report the only case of RDD presenting as an isolated pleural mass. Our patient was a 55-year-old female with multiple comorbidities who presented with chest pain. Imaging revealed an enlarging pleural-based lesion. She underwent resection of the pleural mass, showing an atypical histiocytic infiltrate in a prominent background of collagenous fibrosis. Immunohistochemistry shows CD1a-negative and S100-positive atypical histiocytic cells demonstrating emperipolesis, confirming the diagnosis of RDD. She is currently on six-month CT surveillance with no recurrence of the disease. This case highlights the unique pulmonary presentation of RDD. It also underscores that observations may be appropriate in isolated asymptomatic pleural involvement cases.

Rathinam A ，Gupta S ，Khanam R ，Sahai T ... -  《Cureus》

Cutaneous Rosai-Dorfman disease.

Khoo JJ ，Rahmat BO 《-》

Fine-needle aspiration specimens of 3 cases of intra-abdominal Rosai-Dorfman disease with comprehensive review of the literature.

Rosai-Dorfman disease (RDD) is a rare usually self-limited non-Langerhans cell histiocytosis of unknown etiology. Nodal and extranodal RDD appear to represent distinct conditions with different molecular alterations and prognosis. They also pose different diagnostic challenges on biopsies and fine-needle aspiration (FNA) cytology. The aim of this study was to report on 3 cases of intra-abdominal RDD and perform an extensive review of the literature on FNA findings of RDD. We reviewed FNA specimens from cases diagnosed histologically or cytologically as RDD during the past 10 years. We searched the PubMed and Google Scholar databases for cases of RDD sampled by FNA. We identified 3 cases of intra-abdominal RDD, involving the kidney, periportal lymph node, and pancreas. FNA of the latter was hypocellular with fibrosis and was nondiagnostic. FNA of the first 2 yielded hypercellular smears that were diagnosed as RDD due to the identification of emperipolesis occurring in large uni- or binucleated histiocytes with large nuclei, fine chromatin, and prominent nucleoli in smears and cell-block sections. Immunohistochemistry showed positive staining for S100 and CD68 and negative staining for CD1a. The large histiocytes with emperipolesis were more difficult to identify histologically and their demonstration required immunohistochemical stains. Our experience and an extensive review of the literature suggest that extranodal RDD can be diagnosed on FNA, and that the recognition of histiocytes with emperipolesis may be less challenging cytologically than histologically. The fibrosis frequently seen in extranodal RDD may lead to nondiagnostic aspirates, however.

McIntire PJ ，Kilic AI ，Chen HH ，Atieh M ，Wojcik EM ，Pambuccian SE ... -  《-》