Iron granules in plasma cells

Plasma cell morphology in multiple myeloma and related disorders

Normal and reactive plasma cells (PC) are easy to ascertain on human bone marrow films, due to their small mature-appearing nucleus and large cytoplasm, the latter usually deep blue after Giemsa staining. Cytoplasm is filled with long strands of rough endoplasmic reticulum and one large Golgi apparatus (paranuclear hof), demonstrating that PC are dedicated mainly to protein synthesis and excretion (immunoglobulin). Deregulation of the genome may induce clonal expansion of one PC that will lead to immunoglobulin overproduction and eventually to one among the so-called PC neoplasms. In multiple myeloma (MM), the number of PC is over 10% in most patients studied. Changes in the morphology of myeloma PC may be inconspicuous as compared to normal PC (30-50% patients). In other instances PC show one or several morphological changes. One is related to low amount of cytoplasm, defining lymphoplasmacytoid myeloma (10-15% patients). In other cases (40-50% patients), named immature myeloma cases, nuclear-cytoplasmic asynchrony is observed: presence of one nucleolus, finely dispersed chromatin and/or irregular nuclear contour contrast with a still large and blue (mature) cytoplasm. A peculiar morphological change, corresponding to the presence of very immature PC named plasmablasts, is observed in 10-15% cases. Several prognostic morphological classifications have been published, as mature myeloma is related to favorable outcome and immature myeloma, peculiarly plasmablastic myeloma, is related to dismal prognosis. However, such classifications are no longer included in current prognostic schemes. Changes related to the nucleus are very rare in monoclonal gammopathy of unknown significance (MGUS). In contrast, anomalies related to the cytoplasm of PC, including color (flaming cells), round inclusions (Mott cells, Russell bodies), Auer rod-like or crystalline inclusions, are reported in myeloma cases as well as in MGUS and at times in reactive disorders. They do not correspond to malignant changes of PC but are related to abnormal synthesis, trafficking, or excretion of the immunoglobulin that is stored in excess within the cytoplasm. Occurrence of crystalline inclusions within PC may be the first anomaly leading to the diagnosis of adult Fanconi syndrome. After a historical perspective, the authors report on the various morphological aspects of PC that may occur in multiple myeloma and related disorders, and discuss about their clinical and pathophysiological significance. Today, morphological identification and accurate determination of % PC within bone marrow remain ancillary criteria for the diagnosis of MM and help for the diagnosis of rare renal disorders.

Rectal Plasmacytoma with Intracellular Hemosiderin in a Dog

An 11-year-old female American Cocker Spaniel was presented with a rectal mass that protruded through the anus. Cytologically, the mass was composed of neoplastic round cells consistent with an extramedullary plasmacytoma. Histiocytic sarcoma, carcinoid tumor, and melanoma were also considered because of the presence of golden-brown cytoplasmic granules. Histopathologic findings and immunohistochemical reactivity for lambda light chains confirmed the cytologic diagnosis of plasmacytoma. Prussian blue staining identified the cytoplasmic granules as hemosiderin. The granules were negative by Fontana Masson and Grimelius histochemistry. To our knowledge, this is the first report of an extramedullary plasmacytoma containing hemosiderin in a dog.

Hematological manifestations of copper deficiency: a retrospective review

Copper deficiency is an established cause of hematological abnormalities but is frequently misdiagnosed. Copper deficiency can present as a combination of hematological and neurological abnormalities and it may masquerade as a myelodysplastic syndrome. We reviewed the records of patients with hypocupremia and hematologic abnormalities identified between 1970 and 2005. Patients with hypocupremia unrelated to copper deficiency (e.g. Wilson's disease) were excluded. Forty patients with copper deficiency and hematological abnormalities were identified. Ten patients (25%) had undergone bariatric (weight reduction) surgery and an additional 14 patients (35%) had undergone surgery on the gastrointestinal tract, most commonly gastric resection. In 12 cases, no cause for copper deficiency was identified. Anemia and neutropenia were the most common hematologic abnormalities identified and the majority of the patients also had neurologic findings, most commonly due to myeloneuropathy. Abnormalities observed on bone marrow examination including vacuoles in myeloid precursors, iron-containing plasma cells, a decrease in granulocyte precursors and ring sideroblasts may be valuable clues to the diagnosis. Copper deficiency is an uncommon but very treatable cause of hematologic abnormalities.

Plasma cells with iron inclusions in two non-alcoholic Chinese women

Plasma cells with iron granules are rare, especially among non-alcoholic individuals. We report two teetotaller Chinese women with nasopharyngeal carcinoma and non-Hodgkin's lymphoma, whose bone marrow studies revealed plasma cells with inclusions morphologically compatible with iron granules. The iron nature of the granules was confirmed by elemental analysis. The clinical significance and the exact mechanism of formation of these iron inclusions in plasma cells remain unknown.

The ultrastructural localization of iron in human bone marrow plasma cells

Ferritin was demonstrated by electron microscopy in bone marrow plasma cells of four patients with multiple myeloma and in one patient with another malignant disease. The ferritin molecules were present in membrane bound vesicles and freely dispersed in the cytoplasm. The plasma cells were often localized around and in close contact with dendritic macrophages, which frequently were laden with ferritin. In some of these plasma cells ferritin was seen at specialized contact zones with macrophage extensions.