Histiocytic sarcomas

Primary nasopharyngeal interdigitating dendritic cell tumor presentation and response to radiation therapy

We report the case of a primary nasopharyngeal interdigitating dendritic cell tumor (IDDCT). A 25-year old male presented with bilateral decreased hearing, double vision, and ataxia. Flexible nasopharyngoscopy reviewed a large mass obstructing and filling the entire nasopharynx. MRI and PET-CT confirmed the presence of the primary tumor and demonstrated bilateral cervical lymphadenopathy. Biopsy of the nasopharynx revealed a hematolymphoid neoplasm with dendritic cell differentiation, most consistent with an IDDCT. The lesion was unresectable. The patient was treated with definitive radiotherapy to 66 Gy to the primary tumor and 50 Gy to the bilateral cervical lymphatics using an IMRT technique. A complete response was achieved and the patient remains disease free at the primary site 23 months after completion of radiotherapy.

Langerhans Cell Sarcoma

Proliferations of Langerhans cells can be histologically divided into cytologically benign Langerhans cell proliferations, which include the clinical syndromes of Langerhans cell histiocytosis, and cytologically malignant Langerhans cell sarcoma. We report a Langerhans cell sarcoma in a 33-year-old male that arose on the posterior thigh with subsequent regional lymph node involvement. Conventional microscopic, immunohistochemical, and ultrastructural analysis confirmed Langerhans cell differentiation. Aberrant CD31 expression, similar to that described previously in Langerhans cell histiocytosis, was prominent in this tumor, possibly enhancing its migratory capabilities.

High incidence, early onset of histiocytic sarcomas in mice with Hertwig's anemia

OBJECTIVE

Histiocytic sarcoma (HS) is a rare, rapidly disseminated, usually lethal tumor in humans. Treatment specific for HS has not been developed primarily due to deficiencies of appropriate animal models with high incidence/early onset. Mice with Hertwig's anemia (an/an) provide a potential model.

METHODS

Here, we compare HS susceptibility in an/an and unaffected control mice maintained on three genetic backgrounds. As a potential therapeutic measure, genetically marked bone marrow is transplanted between high and low susceptibility animals.

RESULTS

HS is detected earlier and the overall incidence is 15-fold higher in WBB6F1(F1)-an/an than in F1-+/?, B6-an/an and -+/? mice. Neither WB-an/an nor their normal WB-+/? littermates present with HS. Liver myelopoiesis and aneuploidy coexist with HS but the former is also rampant (33.7% incidence) in HS-free +/? and an/an mice. Marrow transplantation experiments provide evidence that (1) myelopoiesis is associated with HS and (2) early-onset/high-incidence HS is blocked by using late-onset F1-+/+ mice, as either donor or recipient.

CONCLUSIONS

Homozygosity for an on an F1 genetic background is essential for high-incidence/early-onset HS; myelopoiesis and HS coexist; and therapeutic transplantation may be feasible.

Fine-needle aspiration cytology: True histiocytic lymphoma/histiocytic sarcoma

True histiocytic lymphoma/histiocytic sarcoma is an extremely rare, malignant histiocytic tumor. This report is of such a case in a 52-yr-old woman. Fine-needle aspiration (FNA) smears showed large pleomorphic nuclei, prominent nucleoli, moderately dense abundant cytoplasm, and scattered cells with cytoplasmic vacuoles and some with reniform nuclei. Small numbers of background lymphocytes and benign histiocytes were present as well as many multinucleated tumor cells. The immunophenotype was CD45, Lysozyme, CD68 (PGMI), CD43, and S-100 positive. Genotypic analysis revealed a germline configuration. This type of tumor has a large cytological differential diagnosis and immunophenotyping is essential for diagnosis.

Primary histiocytic lymphoma of the central nervous system: a neoplasm frequently overshadowed by a prominent inflammatory component

True histiocytic lymphoma, as defined by strict criteria, is a very rare neoplasm. We describe three cases occurring as primary tumors in the central nervous system. The patients, two females and one male, ranged in age from 11 to 69 years. The tumors involved the brain in two cases and spinal cord in one, with a size ranging from 7 to 17 mm. Two patients died at 4 months and 8 months, respectively, and one was alive with disease at 5 months. Pathologically, the tumors comprised groups and sheets of noncohesive large cells with pleomorphic vesicular nuclei, distinct nucleoli, and abundant eosinophilic cytoplasm. A dense inflammatory infiltrate consisting of neutrophils, lymphocytes, plasma cells, and histiocytes was present, with multiple foci of necrosis and abscess formation. All three cases demonstrated an identical immunophenotype: positive for CD68 and lysozyme; focally positive for S-100 protein, CD45RB, and CD4; and negative for CD3, CD20, CD21/CD35, CD1a, CD30, ALK1, myeloperoxidase, glial fibrillary acidic protein, and cytokeratin. The proliferative index ranged from 20% to 35%. Ultrastructural examination further confirmed the histiocytic nature of the tumor cells, characterized by irregularly folded or multisegmented nuclei and abundant cytoplasm containing lysosomes; Birbeck granules, interdigitating cell processes, and cell junctions were not found. Although the presence of abundant inflammatory cells could obscure the neoplastic histiocytes, making the distinction from inflammatory conditions difficult, awareness of this unusual histologic feature and the invariable finding of pleomorphic cells in some areas of the lesion permit the correct diagnosis to be made.

Histiocytic sarcoma of the spleen associated with hypoalbuminemia, hypo gamma-globulinemia and thrombocytopenia as a possibly unique clinical entity--report of three cases

We report three patients with histiocytic sarcoma of the spleen associated with severe hypoalbuminemia, hypo gamma-globulinemia and thrombocytopenia. After the clinical diagnosis of splenic tumor of unknown origin was made, all three patients underwent splenectomy. The histiocytic origin of the tumor was confirmed histopathologically and immunohistochemically using a panel of antibodies. In contrast to malignant histiocytosis (MH), which typically reveals severe generalized clinical manifestations and a rapidly fatal course caused by the disseminated proliferation of neoplastic histiocytes, these patients were asymptomatic or showed only mild clinical symptoms for a long period of time until the recurrence was detected by which time the tumor cells had already spread to other organs. All three cases were characteristically associated with hypoalbuminemia, hypo gamma-globulinemia and thrombocytopenia, which returned to normal after splenectomy. Splenic histiocytic sarcoma with the features described here may represent a unique clinical entity, distinct from MH.

Reticulum cell neoplasms of lymph nodes: a clinicopathologic study of 11 cases with recognition of a new subtype derived from fibroblastic reticular cells

Lymph nodes contain nonlymphoid accessory cells including follicular dendritic cells (FDCs), interdigitating dendritic cells (IDCs) and fibroblastic reticular cells (FBRCs). Neoplasms derived from FDCs are uncommon, and those of IDC origin are even more rare. We report the clinicopathologic features of 11 reticulum cell neoplasms, including 2 of FBRC origin. There were seven male patients and four female patients ranging in age from 13 to 73 years. All cases involved lymph nodes (cervical or supraclavicular-6 cases), (abdominal--2 cases), epitrochlear (1 case); two had more than one site of involvement (cervical lymph node and mediastinum--1 case, cervical and abdominal lymph nodes--1 case). One case of FDC tumor had concomitant Castleman's disease, plasma cell variant. Each neoplasm showed similar histology with oval-to-spindle-shaped cells in a storiform or fascicular pattern. Based on immunophenotypic findings, the neoplasms were classified as FDC (five cases), IDC (two cases), FBRC (three cases), and reticulum cell neoplasm, not otherwise specified (one case). The FDC tumors showed immunoreactivity for CD21 or CD35, vimentin, and CD68. The IDC tumors showed strong positivity for S-100 protein and variable positivity for CD68 and CD1a. The cases derived from FBRCs were positive for vimentin, desmin, and smooth-muscle actin. The neoplasm classified as reticulum cell neoplasm, not otherwise specified had similar morphologic features but showed only equivocal positivity for CD68 and vimentin. Follow-up was available for 9 of 11 (82%) cases with a mean of 3.5 years. Four of five patients with FDC tumors were alive with disease when last seen; the fifth is alive and well with no evidence of disease at 4-year follow-up. One patient with IDC tumor had a recurrence in a different nodal site. Two patients with FBRC tumor were disease free at follow-up of 2 years and 8 years, respectively. The patient with reticulum cell neoplasm, not otherwise specified, was alive and disease free 8 years after diagnosis.

Malignant histiocytic disorders in children. Clinical and therapeutic approaches with a nosologic discussion

Malignant histiocytic disorders, other than leukemias, are extremely rare in childhood. Despite unresolved nosologic and terminologic difficulties, they should be classified according to the lineage of the aberrant cells in a given tumor. There are no common and typical clinical presentations, nor are there established treatment modalities available. For the disseminated forms, aggressive systemic treatment modalities--similar if not identical to those used for large cell anaplastic lymphomas--appear to be the best treatment option. For the localized forms, which are primarily dendritic cell sarcomas, a more localized and individualized therapy is appropriate.

Contemporary classification of histiocytic disorders. The WHO Committee On Histiocytic/Reticulum Cell Proliferations. Reclassification Working Group of the Histiocyte Society

Pathologists and pediatric hematologist/ oncologists of the World Health Organization's Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.