Pseudo-Peritoneal Carcinomatosis Presentation of a Crystal-Storing Histiocytosis With an Unmutated Monoclonal κ Light Chain

Abstract

Crystal-storing histiocytosis (CSH) is a rare complication of monoclonal gammopathies caused by accumulation of crystalline material inside macrophages, and it may result in a variety of clinical manifestations depending on the involved organs. Although immunoglobulin κ light chains (LCs) seem to be the most frequent pathogenic component, very few molecular data are currently available.A 69-year-old man presented with a very poor performance status. Remarkable features were mesenteric lymph node enlargement and proteinuria, including a monoclonal κ LC. Light and electron microscopy studies revealed the presence of crystals within macrophages in the lymph nodes, bone marrow, and kidney, leading to the diagnosis of CSH. The pathogenic κ LC variable domain sequence was identical to the germline Vk3-20∗01/Jk2∗01 gene segments, without any somatic mutation, suggesting an extra-follicular B cell proliferation.The patient was successfully treated with 4 cycles of bortezomib and dexamethasone. After a 12-month follow-up, he remains in hematological and renal remission.CSH may present as pseudo-peritoneal carcinomatosis and relate to a monoclonal κ LC encoded by an unmutated gene. Bortezomib-based therapy proved efficacious in this case.

Peritoneal or mesenteric tumours revealing histiocytosis

“…2-10 17 Rare cases of reactive histiocytosis have also been reported, such as crystal storing histiocytosis and nodular histiocytic aggregate of the omentum. [18][19][20] As for our patients, in most of these cases the diagnosis of histiocytosis was not initially suspected. Our large series allows to define the main characteristics of these abdominal histiocytic diseases.…”

“…These gain-of-function mutations are responsible for a constitutive activation of the MAP kinase signalling pathway, and are present in the majority of patients with ECD. [14][15][16][17][18][19][20][21] Analysing this series of patients according to initial diagnoses might be helpful to avoid future misdiagnoses and to shorten diagnostic workup of forthcoming patients. A first group of four patients (#4, #10, #11, #17) were initially diagnosed as sclerosing mesenteritis, two of whom (#10, #11) were finally diagnosed with ECD with typical involvement of long bones, retroperitoneum, skin and/or orbits.…”

Crystal-Storing Histiocytosis: Report of a Rare Case Presenting With Pathological Fracture of Femur. Is There More to the Entity?

“…One other study also has made this observation. 6 In cases not associated with lymphoid or plasma cell neoplasms, there had been inflammatory background with hyperactivated immune system in the form of rheumatoid arthritis, Sjogren syndrome, and so on. 1 Then it is reasonable to hypothesize that a proportion of the patients with monoclonal and possibly polyclonal gammopathy possess a clone of plasma cells with specific immunoglobulin (Ig) gene rearrangements which lead to overproduction and/or secretion of these modified defective immunoglobulins with abnormal crystallization properties, which in turn recruit the histiocytes.…”

Light Microscopic Studies on the Morphology of Tissues Embedded in Epoxy Resin

“…1,4,8,10,11 Unfortunately its general lack of polycromasia makes it unsuitable for photomicrography. Much better results are obtained for general work as well as for photomicrography (especially with the use of filters for the black and white film) with the methylene blue, azure II combinations.…”