Analysis of Monocyte and Histiocytic Cell Populations in Bone Marrow of Patients with Confirmed and Suspected Cases of Reactive Histocytosis

Granular variant of a histiocytic tumor on the toe of a cat: Case report and literature review

A 16-year-old female spayed domestic shorthaired cat was examined for lameness and a mass on the fourth digit of the right hindlimb. Cytologic examination of an aspirate of the mass revealed large discrete cells admixed with low numbers of well-granulated mast cells. The discrete cells contained single to many variably sized light pink to purple granules in their cytoplasm and had pleomorphic nuclei, with intranuclear cytoplasmic inclusions. Karyomegalic, binucleated and multinucleated cells were seen. Histologic examination of formalin-fixed sections of the excised mass showed a mildly infiltrative, unencapsulated, multinodular dermal mass that extended into the subcutis and consisted of similar discrete cells. On immunohistochemical staining, the tumor cells expressed ionized calcium-binding adapter molecule 1 (Iba1) and CD18. The tumor cells did not express CD3, CD20, CD117, pancytokeratin (AE1/AE3), melanoma antigen (Melan-A), multiple myeloma oncogene-1 (MUM1), melanoma-associated antigen (PNL-2), and S-100. Low numbers of tumor cells expressed CD204 and protein gene product 9.5 (PGP9.5). Granules were variably positive for Periodic-acid Schiff (PAS) and Alcian blue. On transmission electron microscopy, the cells contained filopodia, abundant endoplasmic reticulum, and moderate numbers of low-density membrane-bound granules. This case documents a previously undescribed granular variant of a histiocytic tumor in a cat.

Reactive Hemophagocytic Lymphohistiocytosis Secondary to Ovarian Adenocarcinoma: A Rare Case Report

Background

Hemophagocytic lymphohistiocytosis (HLH), a syndrome of immune hyperactivation and abnormal regulation that causes life-threatening inflammation, is mainly characterized by fever, hepatosplenomegaly, cytopenia, and other symptoms. Reactive HLH (rHLH) is typically secondary to immune deregulation caused by underlying rheumatologic, infectious, or malignant conditions. Malignancy-associated HLH (M-HLH) continues to be a critical health problem worldwide. Most malignancies associated with HLH are hematologic tumors, and M-HLH in non-hematologic tumors very rarely occurs.

Case Report

A 34-year-old Chinese woman had a history of persistent fever, acute dizziness, and bicytopenia. She was found to have developed bilateral ovarian cancer. Additional tests showed splenomegaly, hemophagocytes in the bone marrow, low natural killer activity, and hyperferritinemia, which met the diagnostic criteria put forth in the Histiocyte Society HLH-2004. The patient was treated with correcting anemia, increased platelets, and glucocorticoid therapy but showed no response. She progressively deteriorated and died 55 days later.

Conclusion

Hemophagocytic lymphohistiocytosis related to a solid tumor is extremely rare. To the best of the authors’ knowledge, the present case was the first to report rHLH secondary to ovarian adenocarcinoma. It is very significant for a better understanding of the disease mechanisms of HLH and should attract the attention of hematologists and other clinicians as the condition progresses and the cost of treating it increases.

Foam cell origination from degenerated vascular smooth muscle cells in atherosclerosis: An ultrastructural study on hyperlipidemic rabbits

To clarify foam cell origination in atherosclerosis, a series of morphologic and ultrastructural alterations of vascular smooth muscle cells (VSMCs) and foam cells were studied by light and electron microscopy in atherosclerotic aortas from hyperlipidemic rabbits induced for 5 weeks. The study exhibited that VSMCs were severely degenerated and damaged, including irregular shapes, expanded mitochondria, aplenty lipid droplets, and disarranged myofilaments in cytoplasm in media adjacent to atheromatic bottoms. Most lipid laden cells shared interphase structures of VSMCs and foam cells, and some dissolved spindle cells contained lipid droplets, lipofuscin, and rod-like CCs in cytoplasm also. The result demonstrated that VSMCs were degenerated and transformed into foam cells in atherosclerosis, which was responsible for the accumulation of lipid and cholesterol crystals in atherosclerotic arteries.

One cell one niche: hematopoietic microenvironments constructed by bone marrow stromal cells with fibroblastic and histiocytic features

Hematopoietic microenvironments have been extensively studied, especially focusing on regulation of hematopoietic stem cells (HSCs) in HSC niche following progress of molecular biology in resent years. Based on prior morphological achievements from 1970s, the characteristics of cellular compartments and bone marrow stromal cells (BMSCs) were studied ultrastructurally in human and mice bone marrow in the present study. The samples, human bone marrow granules, were collected from bone marrow aspirations (BMAs) of 20 patients with hematocytopenia and isolated BMSCs were found undesignedly in nucleated cells of BMAs of the patients. Femoral bone marrow samples were collected from 6-week-old three sacrificed mice. Detailed images illustrated maturing hematopoietic cells harbored individually in honeycomb-like microenvironment constituted by BMSCs that shared of fibroblastic and histiocytic characteristics in hematopoietic microenvironments of human and mice bone marrow.

Activation of monocyte-derived cells in the bone marrow of myelodysplastic syndrome

OBJECT

To study the relationship between monocyte/histiocyte activation and myelodysplastic syndrome (MDS).

METHODS

Analyzing ultrastructure and myeloperoxidase reaction of nucleated cells in bone marrow from 59 cases of MDS by transmission electron microscopy. Four groups of MDS were subdivided on the basis of their content of activated inflammatory cells - morbid hematopoiesis with minimal inflammatory cell activation (MH-MICA); MDS with monocytic system activation (MSA); MDS with lymphocyte activation (LCA); and MDS with granulocyte activation (GCA).

RESULTS

About 20, 22, 7, and 10 cases were classified as MH-MICA (34%), MSA (37%), LCA (12%), and GCA sub-types (17%), respectively. About 3, 5, 0, and 3 cases from MH-MICA, MSA, LCA, and GCA, respectively, underwent leukemic transformation within 2 years.

CONCLUSION

The findings suggest that activation of inflammatory cells in bone marrow is an important feature of MDS, and that monocytes/histocytes are perhaps the most prominent cellular participants in the pathogenesis of MDS.