Congenital Rosai-Dorfman disease presenting with anemia, thrombocytopenia, and hepatomegaly

Histiocytic Diseases of Neonates: Langerhans Cell Histiocytosis, Rosai-Dorfman Disease, and Juvenile Xanthogranuloma

Langerhans cell histiocytosis, Rosai-Dorfman disease, and juvenile xanthogranuloma may present at birth or any time afterward. Some patients have minimal skin or lymph node involvement, but others present with life-threatening pulmonary, hepatic, bone marrow, or central nervous system lesions. There is often a delay in diagnosis because of confusing overlap with more common neonatal diseases. Many treatment regimens have been applied to these diseases, but those directed at myeloid cells, such as cytarabine and clofarabine or mutation-targeting inhibitors, are gaining favor. This article provides information on the pathophysiology, clinical presentation, evaluation guidelines, and treatment of these uncommon tumors of neonates.

Expanding the Phenotype of ALK-positive Histiocytosis: A Report of 2 Cases

ALK-positive histiocytosis is a recently described rare histiocytic proliferative disorder of early infancy. When infants present with anemia, thrombocytopenia, and hepatosplenomegaly, this entity should be included in the differential diagnosis along with hemophagocytic lymphohistiocytosis, metabolic/storage diseases, hematopoietic malignancies, and autoimmune thrombocytopenia. We report 2 new cases of ALK-positive histiocytosis, one with kidney involvement and the other with extensive bone marrow involvement in addition to an overt liver disease. Renal involvement by ALK-positive histiocytosis has not been reported. The infiltrating histiocytes in this case showed Rosai-Dorfman disease-like morphology including emperipolesis. The histiocytes in the second case with extensive bone marrow involvement had foamy cytoplasm initially suggesting storage disease. Our 2 cases highlight previously unrecognized diversity of ALK-positive histiocytosis in clinical manifestation, organ involvement, and cytomorphologic features and further elucidate the diagnostic challenges of this rare entity.

Cytomorphological and morphometric analysis of 22 cases of Rosai-Dorfman disease: a large series from a tertiary care centre

BACKGROUND

Rosai-Dorfman disease (RDD) is a rare benign idiopathic histiocytic proliferation. Most commonly reported cases are lymph nodal. Only 30-40% of cases occur in extranodal sites. Although the morphological features of RDD are well documented, there is limited information about the morphometric variations in the histiocytes of this entity.

METHOD

Twenty-two cases of RDD diagnosed on fine-needle aspiration cytology (FNAC) were retrieved from the archives. Both Papanicolaou- and May-Grünwald-Giemsa-stained slides were available for evaluation in all cases. Nuclear area, diameter and histiocyte size were measured taking reactive histiocytes as controls.

RESULTS

Among the 22 patients (male/female ratio 3:2; age range 5-55 years, mean 26 years), 3 cases were extranodal and 19 cases were nodal. The nodal sites included cervical, axillary, inguinal and submandibular lymph nodes. The extranodal sites were the retroperitoneum, mediastinum and skin. The most common clinical presentation was enlarged lymph nodes. Cytological features included numerous large benign histiocytes with emperipolesis. All the morphometric parameters were significantly (p < 0.01) higher in RDD histiocytes than in histiocytes in the reactive lymph node.

CONCLUSIONS

In view of the rarity of the disease and the variable clinical presentation in RDD, accurate diagnosis is necessary. This is the first study to document the morphometric parameters of RDD histiocytes and their comparison with histiocytes in the reactive lymph node.