Immunohistochemical localization of lysozyme, lactoferrin, alpha 1-antichymotrypsin, and alpha 1-antitrypsin in salivary gland of human fetuses.

26 human fetuses were examined to elucidate the immunohistochemical distributions of lysozyme, lactoferrin, alpha 1-antichymotrypsin, and alpha 1-antitrypsin in prenatal salivary glands. Development of fetal salivary glands was divided into 4 stages: The early developmental stage (EDS), the early intermediate developmental stage (EIDS), the late intermediate developmental stage (LIDS), and the late developmental stage (LDS) and were used to compare antigen localization during salivary gland development. Lysozyme (LY) staining was prominent in serous or demilune cells of the mucous acinar compartment. Lactoferrin (LF) was rarely seen in the fetal glands; only trace amounts were seen in serous cells, alpha 1-antichymotrypsin (alpha 1-ACT) was diffusely positive particularly in glandular ducts, alpha 1-antitrypsin (alpha 1-AT) was also diffusely distributed in all salivary gland elements and was more abundant in ductal cells than acinar cells. During the EDS, immunohistochemical staining of LY, LF, alpha 1-ACT, and alpha 1-AT could be observed with glandular intensity increases corresponding to the advance of cytodifferentiation of granular epithelium occurring in the subsequent EIDS and LIDS. Staining intensities were continuous during the LDS even though the amount of those materials in the fetal salivary glands was not of the extent seen in the adult salivary gland. These results suggest that production of LY, LF, alpha 1-ACT, and alpha 1-AT was positive during prenatal development of human salivary glands. The present study discusses the protective roles and defense mechanisms of LY, LF, alpha 1-ACT, and alpha 1-AT in developing human salivary glands.     

A histiocyte-specific marker in the diagnosis of malignant fibrous histiocytoma. Use of monoclonal antibody KP-1 (CD68)

KP-1 (CD68) is a recently described monoclonal antibody to a cytoplasmic epitope present on tissue histiocytes and macrophages. To determine the specificity and sensitivity of this marker in the evaluation of cases of malignant fibrous histiocytoma (MFH), this reagent and a panel of commercially antibodies were used to stain formalin-fixed paraffin sections from 25 cases of MFH and 25 other tumors, including a variety of soft-tissue sarcomas. Eighteen of 25 cases of MFH stained for KP-1 (72%), whereas all other tumors were negative, including 12 cases of pleomorphic soft-tissue sarcoma other than MFH. The percentage of tumor cells staining for KP-1 varied. In 11 cases KP-1 was only focally present, but staining was of a high intensity and associated with minimal nonspecific or background staining. Pleomorphic histiocytic cells and spindle cells from storiform tumors were strongly decorated with antibodies to KP-1 in most cases, and antigen also was present on tumor giant cells. Although alpha-1-antitrypsin and alpha-1-chymotrypsin stained a higher percentage of cases of MFH (92%), immunoreactivity for these markers also was noted in other tumors. Because of its specificity as a histiocyte marker, KP-1 is a useful component in a panel of antibodies for the characterization of soft-tissue sarcomas and the diagnosis of MFH.     

Distribution of tissue markers in acinic cell carcinomas of salivary gland.

Eight cases of acinic cell carcinoma of the salivary glands were histologically reclassified and their immunohistochemical expression and distribution for various tissue antigens were examined. The epithelial elements were divided into tubuloglandular components, microcystic patterns and solid nests. The authors' results indicated the following: 1) The duct luminal cells of tubuloglandular components have distinct epithelial features with cytokeratin (KL 1), alpha 1-antichymotrypsin (alpha 1-ACT), transferrin, lactoferrin, IgA, and carcinoembryonic antigen (CEA) positivity. 2) The cyst-lining cells of microcystic pattern expressed immunophenotypes similar to those of the duct luminal cells. 3) The acinic cells in solid nests had positive results for KL 1, alpha 1-antitrypsin (alpha 1-AT), transferrin, lactoferrin and vasoactive intestinal polypeptide (VIP). 4) The clear cells in solid areas had positive results for KL 1, alpha 1-AT, transferrin and VIP. Both the clear cells and the neoplastic acinic cells showed a rather similar pattern of immunoreactivity. Therefore, the clear cells may transform from the neoplastic acinic cells. 5) Secretory products in tubuloglandular and microcystic patterns had positive results for alpha 1-ACT, lactoferrin, IgA and CEA. 6) The basement membrane-like material between the neoplastic islands has distinct positivity for alpha 1-AT. The result suggests that alpha 1-AT is a useful marker of basement membrane-like material.     

Immunohistochemical investigation of vimentin, neuron-specific enolase, alpha 1-antichymotrypsin and alpha 1-antitrypsin in adenoid cystic carcinoma of the salivary gland

Fifty-four adenoid cystic carcinomas (ACC) arising in major and minor salivary glands as well as in normal salivary glands were studied by immunohistochemistry for the presence of vimentin, neuron-specific enolase (NSE), alpha 1-antichymotrypsin (alpha 1-ACT) and alpha 1-antitrypsin (alpha 1-AT). Five patterns of histological differentiation were found in ACC, and for the cellular components of each, it was possible to establish a special immunohistochemical profile. In ACC, vimentin-positive cells were observed in the outer tubular, cyst-lining and small angular cells. NSE was positive in the myoepithelial cells of normal salivary gland. Neoplastic cells of ACC showed NSE positivity mainly in the small angular cells and partly in the duct luminal cells. alpha 1-ACT was localized in the intercalated duct cells and serous acinar cells of normal salivary gland, and in the duct luminal cells of ACC. alpha 1-AT could not be detected in any of the epithelial cells of normal salivary gland. In ACC, eosinophilic hyaline material in the cribriform spaces was positive for alpha 1-AT, but no positivity was demonstrated in tumor cells. The present study showed that there are at least two populations of tumor cells in ACC: duct luminal cells that express alpha 1-ACT, thus indicating their ductal character, and small angular cells that express vimentin, characteristic of non-luminal cells. Moreover, our results indicate that alpha 1-AT is a useful marker of basement membrane-like material.     

Characterization of tumor cells in malignant fibrous histiocytomas and other soft-tissue tumors, in comparison with malignant histiocytes. II. Immunoperoxidase study on cryostat sections.

The authors have investigated a possible relationship between tumor cells of malignant fibrous histiocytomas (MFHs) and histiocytes. This relationship was studied by means of immunophenotyping using monoclonal antibodies specific for the monocyte cell lineage (FMC-17, Mac-1, OKM-1, Leu-M1, and lysozyme) and mono- and polyclonal antibodies specific for fibroblasts (respectively, FIB-86 and FSG). The immunophenotypes of the MFH tumor cells were compared with those of tumor cells of "true" histiocytic tumors. Monocyte lineage-specific determinants could be demonstrated in varying amounts on cells of the "true" histiocytic tumors but not on cells of MFH or other soft-tissue tumors. The reverse was true for determinants on fibroblasts. The absence of these determinants on malignant histiocytes, and their presence on MFH (and also on benign fibrous histiocytomas, fibrosarcomas, schwannomas, osteosarcomas, hemangiosarcomas, leio- and rhabdomyosarcomas) supported the conclusion that MFH tumor cells originate from mesenchymal cells which do not belong to the mononuclear phagocytic system. Subdivision of the MFH tumors revealed that the storiform-pleomorphic subtypes could express HLA-Dr/Ia antigens, like histiocytic tumors. The inflammatory cell subtype, however, lacked these antigens.     

Immunoreactivity of normal and neoplastic human tissue mast cells

Immunoreactivity of human tissue mast cells (TMCs) was studied in one case of solitary mastocytoma of the skin, three cases of malignant mastocytosis, and in six lymph nodes with reactive intrasinusoidal increase of TMCs. Immunohistochemically, TMCs reacted positively to antisera against vimentin, common leukocyte antigen (CLA), lysozyme, alpha 1-antitrypsin (alpha 1-AT), and alpha 1-antichymotrypsin (alpha 1-ACT) and to a monoclonal antibody (KiB3) that detects preferentially B-lymphocytes. Additionally, strong positive reactions to polyclonal antisera against adrenocorticotropic hormone (ACTH) and human peptide histidine isoleucine (PHI) and weaker reactions to antisera against leu-enkephalin and met-enkephalin were observed; all other antisera tested yielded negative results. Positive stainings for vimentin, CLA, alpha 1-AT, alpha 1-ACT, and lysozyme further support the hypothesis that human TMCs may be related to the myeloid-monocytic system. The positive reactivity of TMCs to antisera against ACTH, PHI, leu-enkephalin, and met-enkephalin has not been reported previously. These findings suggest that TMCs are able to store and/or produce regulatory peptides in addition to many other well-known, granule-bound mediators.     

Immunohistochemical demonstration of alpha1-antichymotrypsin and alpha1 -antitrypsin in the normal pituitary gland and its tumors

The immunohistochemical distribution of the protease inhibitors alpha₁-antichymotrypsin (alpha₁-ACT) and alpha₁-antitrypsin (alpha₁-AT) has been documented in the normal human pituitary gland and in a series of pituitary tumors. In normal gland, alpha₁-ACT was localized mainly in the dendritic folliculostellate cells, identified by immunopositivity for S 100 protein. A minority of endocrine cells also stained in 3 of 10 autopsy glands. Folliculostellate cells were identified in 11 of 28 tumors, and again, the distribution of alpha₁-ACT positivity corresponded to these cells. In 4 cases, there was staining of a small minority of tumor cells. Alpha₁-AT was localized to colloid in the microfollicles of the anterior lobe. In I normal gland, there was granular staining of endocrine cells. Alpha₁-AT was present in 5 tumors, in microfollicles and in scattered endocrine cells in 2 adenomas. These data would support a physiological role for alpha₁-ACT and alpha₁-AT in the pituitary gland. Their differing distribution might reflect different functions.     

Immunohistochemical investigations of tumors of supposed fibroblastic-histiocytic origin

The aim of this study was to localize alpha 1-antitrypsin, ferritin, and lysozyme by means of the indirect immunoperoxidase technique and to evaluate the significance of these antigens as markers of histiocytic differentiation in tumors of a supposed dual fibroblastic-histiocytic origin. The series comprised 31 malignant fibrous histiocytomas (MFH) of the pleomorphic, spindle cell, and myxoid types, four cutaneous fibrous histiocytomas, and four atypical fibroxanthomas, four dermatofibrosarcoma protuberans, and two osteoclastomas of bone. For comparison, 15 soft tissue sarcomas of various other types were examined. Of the MFHs of the pleomorphic type, 18 of 22 (82 per cent) were positively stained for alpha 1-antitrypsin and 12 of 22 (54 per cent) were positively stained for ferritin. Of the five MFHs of the spindle cell type, none was positively stained for alpha 1-antitrypsin, three were positive for ferritin, and one was positive for lysozyme. None of the myxoid variants (corresponding to grade I-II myxofibrosarcoma) was positively stained for either of the antigens. These results and the observations made on the cutaneous fibrous histiocytomas, atypical fibroxanthomas, dermatofibrosarcoma protuberans, and the various soft tissue sarcomas indicated that 1) alpha 1-antitrypsin is a valuable marker of histiocytic differentiation in both benign and malignant fibrous histiocytomas, 2) ferritin can be visualized in more than half of these fibroblastic-histiocytic tumors, and the presence of ferritin distinguishes the spindle cells of these tumors from fibroblasts of connective tissue and most fibrosarcomas, and 3) lysozyme, although a good marker of histiocytic differentiation in ordinary histiocytes and benign fibrous histiocytomas, is a poor marker of neoplastic histiocytes of malignant tumors. The results further support the concept that MFH is a tumor of a dual fibroblastic-histiocytic origin.     

Demonstration of alpha 1-antitrypsin in hepatomas.

Sixty-nine primary malignant hepatomas were examined for the presence of alpha 1-antitrypsin (alph 1-AT) in tumor cells using immunohistochemical methods. Twenty-eight tumors showed positivity for alpha 1-AT. The reaction was globular and PAS-positive in 12 hepatocellular tumors and thus simulated the pattern of alpha 1-AT accumulation in hepatocytes in subjects carrying the Z-gene for alpha 1-AT. In fact, eight of these 12 tumors presented this pattern in the nontumours liver tissue. In ten hepatocellular tumors the reaction was finely granular throughout the hepatocytic cytoplasm, but was present in only a small number of cells. Still fewer cells were positive in six cholangiocarcinomas. The globular alpha 1-AT in tumor cells may be genetically determined when associated with the Z-gene. A reappearance of fetal gene products may be assumed in three hepatocarcinomas with globules positive for alpha-fetoprotein as well as alpha 1-AT.     

Cytokeratin immunoreactivity in malignant fibrous histiocytoma and spindle cell tumors: comparison between frozen and paraffin-embedded tissues.

Cytokeratin (CK) immunoreactivity in malignant fibrous histiocytoma (MFH) and other selected cases of spindle cell tumors were assessed using two cytokeratin monoclonal antibodies, AE1/AE3 and CAM 5.2. Frozen tissue was used to minimize the effects of fixation on keratin antigenicity; in addition, one block of fixed, paraffin-embedded tissue was tested for comparison. CK immunoreactivity was noted in nine frozen tissue samples (7/20 [35%] MFH, 1/3 schwannomas, 1/3 leiomyosarcomas). In the majority of cases, only rare individual positive cells were seen. Of 19 MFH cases in paraffin-embedded tissue, CK immunoreactivity was noted in three (16%). All 32 cases examined showed vimentin immunoreactivity. MFH must be added to the growing list of mesenchymal tumors exhibiting sporadic CK immunoreactivity. Such reactivity is less frequent in paraffin-embedded tissues. This finding has important implications for tumor diagnosis, particularly in the differential diagnosis of pseudosarcomatous carcinoma. Caution is recommended in the interpretation of CK immunoreactivity, particularly as it relates to speculations regarding histogenesis.     

The use of clustering software for the classification of comparative genomic hybridization data. an analysis of 109 malignant fibrous histiocytomas

Malignant fibrous histiocytoma (MFH) is considered the most frequent soft-tissue sarcoma of late adult life. Nevertheless, the validity of this entity has been recurrently questioned by pathologists. Preliminary analyses by comparative genomic hybridization (CGH) of series of MFH have suggested that this tumor group is heterogeneous at the genomic level, and that at least two main genetic subgroups exist. We report an analysis by CGH of a large series of 109 MFH and on the use of clustering software for an objective classification of these tumors. We confirm our preliminary CGH results and demonstrate that two main clusters of tumors are present in the series analyzed.     

Factor XIIIa and the classic histiocytic markers in malignant fibrous histiocytoma: a comparative immunohistochemical study

Fifteen cases of malignant fibrous histiocytoma (MFH) and 79 cases of differential-diagnostically related soft tissue tumors were evaluated for immunoreactive cells for the subunit A of factor XIII (F-XIIIa) in comparison with the staining obtained by the classic histiocytic markers: lysozyme, alpha 1-antitrypsin (AAT) and alpha 1-antichymotrypsin (AACT). Ubiquitous and focal staining patterns were distinguished. Only three cases of MFH were characterized by an ubiquitous positive reaction for AAT and AACT, in contrast to the obligatory positive staining of MFH for F-XIIIa. This low ratio is probably related to the high proportion of predominantly fibroblastic and myxoid types of MFH (11/15). In the three cases of MFH characterized by ubiquitous positive reactions for both antiproteases and for F-XIIIa, the frequency of positive cells for AAT and AACT exceeded that for F-XIIIa. Thus, the positive cells for antiproteases and those for F-XIIIa represent different levels of fibro-histiocytic differentiation; the F-XIIIa-positive cells are fibro-histiocyte precursors. F-XIIIa-positive stromal cells are present in the normal mesenchyme, but their significance is unknown. The fact that these cells are a constant feature of MFH argues for a histiocytic pathway of their differentiation. The ubiquitous presence of F-XIIIa-positive cells in MFH distinguishes them from the histologically similar soft tissue tumors. However, the focal presence of F-XIIIa-positive cells indicate only a host response to an unspecified tissue injury that may occur in all kinds of soft tissue tumors.     

Characterization of tumour cells in malignant fibrous histiocytomas and other soft tissue tumours in comparison with malignant histiocytes. I. Immunohistochemical study on paraffin sections

We have studied the possible origin of histiocytic cells, present in fibrous histiocytomas (MFH) by using immunohistochemistry to demonstrate lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin and receptors for peanut and soy bean agglutinin in tumour cells of MFH compared with their presence in tumour cells of malignant histiocytosis (MH) ('true' histiocytic lymphoma, 'true' histiocytic sarcoma). We included in this study a number of other soft tissue tumours (STT). Lysozyme was detected in half of the cases of malignant histiocytosis (n = 16) but in only two out of 77 MFH. alpha 1-Antitrypsin and alpha 1-antichymotrypsin usually occurred together although the latter was seen in more cases. Both markers were present in majority of cases of MH whereas they were detected in a minority of cases of MFH. MFH cases of the storiform subtype were less frequently stained than the pleomorphic or giant cell subtypes. Receptors for peanut or soy bean agglutinin were detected in nearly all MH cases, whereas their presence was only detected in a small number of MFH. Lysozyme was not detectable in other STT. alpha 1-Antitrypsin and alpha 1-antichymotrypsin were uncommonly present in other STT, except in osteosarcoma and rhabdomyosarcoma. These markers therefore have a limited value as indicators of a possible histiocytic origin of MFH. Lectins showed weak affinity for other STT. In accordance with others, we therefore conclude that the progenitor cell of MFH has to be sought within the undifferentiated mesenchymal cells and that histiocytes themselves probably do not give rise to MFH.     

Methods in pathology. Immunophenotype of hairy cell leukemia in paraffin sections

The immunophenotype of hairy cell leukemia (HCL) was investigated using 20 routinely fixed paraffin-embedded tissue sections (12 bone marrows, six spleens, one liver, one lymph node) from 12 patients known to have this disease. A panel of antibodies was used, including anti-leukocyte common antigen (anti-LCA), B-lineage antibodies (LN2, MB2, L26), T-lineage reagents (MT1, UCHL1), monocytic (anti-cathepsin B) and myelomonocytic (anti-lysosyme, Mac 387) antibodies, and other less lineage-specific markers (anti-S-100, anti-alpha-1-antichymotrypsin (anti-alpha 1-ACT), anti-alpha 1-antitrypsin (anti-alpha 1-AT), anti-vimentin). Anti-LCA stained hairy cells in seven of the 12 bone marrows and consistently recognized hairy cells in the spleen, liver, and lymph nodes. Hairy cells generally reacted with B-lineage antibodies and were not labeled by T-lineage markers. No reactivity was noted with myelomonocytic antibodies, anti-S-100, anti-alpha 1-ACT, or anti-alpha 1-AT. Vimentin was expressed in the majority of cases. Tartrate-resistant acid phosphatase reactivity was demonstrated in three of the 20 routinely processed tissue sections. These data suggest that immunohistochemical studies of hairy cell leukemia in routinely processed tissue may be useful in diagnostic hematopathology and surgical pathology.     

The significance of double phenotypic patterns and markers in human sarcomas. A new model of mesenchymal differentiation.

Six soft-tissue sarcomas with two separate and juxtaposed histologic patterns were selected for immunohistochemical analysis. The first pattern was represented by five phenotypes (schwannian-skeletal muscle [Triton], cartilagenous, synovial, adipocytic, and smooth muscle). In each case the second histologic pattern resembled the fibrohistiocytic phenotype, ie, malignant fibrous histiocytoma (MFH). No other histologic patterns were identified. Appropriate cell markers were demonstrated in each of the first patterns; these were not detected in the second patterns. In contrast, the second pattern in all cases expressed alpha 1-antichymotrypsin, a marker commonly found in fibrohistiocytic lesions; this was not identified in any of the first patterns. This loss of one cell-specific marker and gain of another is termed the "antigenic shift" phenomenon and appeared to foretell the emergence of a true second phenotype (the same in each of these cases, which could be termed "dedifferentiated" sarcomas). Therefore, it is hypothesized that MFH is a final common pathway for some types of sarcomas and is the result of tumor progression or "dedifferentiation." The practical implications of this hypothesis concern the approach to sarcoma differential diagnosis and the meaning of an MFH pattern in both metastatic and primary sites. On a theoretic level, this hypothesis and the antigenic shift phenomenon force a reconsideration of the pathways of soft-tissue differentiation. A new model of mesenchymal differentiation incorporating these concepts is described and supported. It provides an explanation for a number of facts in soft-tissue pathology, and its predictions can be tested.     

Malignant fibrous histiocytoma. Evidence of perivascular mesenchymal cell origin immunocytochemical studies with monoclonal anti-MFH antibodies.

Using whole cell antigens prepared from the established lines of human malignant fibrous histiocytoma (MFH), the authors have generated two different monoclonal antibodies (FU3 and FU4) by a mouse hybridoma technique. By indirect immunoperoxidase in frozen tissue sections, FU3 and FU4 revealed strong staining of perivascular mesenchymal cells and fibroblasts. In the spleen FU3 stained perivascular cells of the ellipsoids and the marginal zone of the lymph follicles. Macrophages in granulation tissues as well as monocytes and other blood cells in normal peripheral blood were uniformly negative for the antigen detected by FU3. Among various soft-tissue tumors, MFH and liposarcoma reacted strongly with FU3 and FU4, but synovial sarcoma revealed no reaction with either of the antibodies. Immunoelectron-microscopic studies demonstrated positive reactions with FU3 and FU4 on the surface of MFH cell membrane, which suggests that these antibodies recognized cell surface antigens. In conclusion, MFH shares antigenicity with perivascular mesenchymal cells and fibroblasts as well as liposarcoma. MFH and liposarcoma may have a common origin from the perivascular mesenchymal cells that are supposed to have a potential for multidirectional differentiation.     

A correlative cytologic and histologic study of malignant fibrous histiocytoma: an analysis of 40 cases examined by fine-needle aspiration cytology

A correlative cytologic and histologic study of 40 cases of histologically highly pleomorphic malignant fibrous histiocytoma (MFH) is presented. The fine-needle aspiration biopsy was performed preoperatively, and a diagnosis of malignant soft-tissue tumor could be established in all cases. The cytologic and histologic features corresponded well with each other. The two main cell types were mono- and multinucleated, large polymorphic, often bizarre, histiocyte-like cells and atypical fibroblast-like cells. For a correct diagnosis of pleomorphic MFH, it is important to recognize atypical large polymorphic tumor cells showing signs of phagocytosis: prominent cytoplasmic vacuolization, cell debris or even well-preserved cells within the tumor cell cytoplasm. Phagocytic activity was easily demonstrated in air-dried and May-Grünwald Giemsa-stained material. The differential diagnosis of MFH as opposed to other soft-tissue sarcomas and pleomorphic carcinomas is discussed.     

Malignant fibrous histiocytoma with special reference to its differential diagnosis

The histological diagnosis of malignant fibrous histiocytoma (MFH) seems to have become recently fashionable among pathologists, although its histogenesis and diagnostic criteria are not entirely settled as yet. For practical purposes the differential diagnosis with other easily mistakable mesenchymal tumors should be strictly made with great caution, because of variable histological features of this tumor. The authors attempted to elucidate the differential points from other tumors in a review of 189 cases of malignant soft tissue tumors. Some cases of carcinoma mimicking MFH were also reviewed. No single criterion for making the histological diagnosis of MFH was obtained. Its histological features and differential points from pleomorphic rhabdomyosarcoma and fibrosarcoma were tabulated. The recognition of a true tumor osteoid was emphasized as a single differential point between osteosarcoma and MFH often with fibrous areas mimicking osteoid. Renal cell carcinoma metastasizing to bone, which was misinterpreted as MFH on biopsy tissue, was also described and its differential point was stated.     

Flow cytometric DNA analysis of malignant fibrous histiocytoma and related fibrohistiocytic tumors

Fibrohistiocytic neoplasms with similar histologic characteristics may have vastly different biologic behaviors. We studied 23 fibrohistiocytic tumors to determine if cellular DNA content was correlated with clinical outcome. Archival paraffin blocks of 9 malignant fibrous histiocytomas (MFH), 3 dermatofibrosarcoma protuberans, 9 dermatofibromas, 1 juvenile xanthogranuloma, and 1 nodular fasciitis were processed, stained with propidium iodide, and analyzed by flow cytometry. Five of 9 (56%) MFH and 1 of 3 (33%) dermatofibrosarcoma protuberans were aneuploid. All 11 benign fibrohistiocytic tumors were diploid. Local recurrence occurred in 3 of 5 (60%) cases of aneuploid MFH, but in none with a diploid MFH tumor. No cases of dermatofibrosarcoma protuberans or benign tumors recurred. Aneuploidy was associated with decreased survival, as 2 of 5 patients with aneuploid MFH died within 1 year of diagnosis whereas all 4 patients with diploid MFH tumors are alive after an average follow-up of 4 years (range, 1 to 11). The diploid and aneuploid groups did not differ in clinical stage at the time of diagnosis. Our results indicate that retrospective DNA analysis can detect aneuploidy in both MFH as well as other fibrohistiocytic tumors, and that aneuploidy in MFH may place the patient at increased risk for local recurrence and mortality.     

Immunohistochemistry of markers of histiomonocytic cells in malignant fibrous histiocytomas. A monoclonal antibody study

Nine cases of malignant fibrous histiocytomas (MFH) were examined immunohistochemically in frozen sections with six different monoclonal antibodies to histiomonocytic and related cells (EBM11, HAM-56, KB90, antibodies to dendritic reticulum cells, HLADR and LCA). Ten other soft tissue sarcomas, two desmoid tumors, twelve carcinomas, three seminomas and four lymphomas were studied for comparison. All cases of MFH showed positivity for histiomonocytic cell antigens. In six cases, the positive cells could be clearly interpreted to be infiltrating non-neoplastic cells. However, immunoreactivity for multiple histiocytic markers (EBM11, HAM-56, KB90, HLADR) was seen in tumor cells in three cases of MFH. In one of these cases, the positivity could be verified with KP1, an antibody to histiomonocytic cells applied in formalin fixed and paraffin embedded tissue. None of the tumors was positive with the antibody to dendritic reticulum cells or LCA. In the series of non-histiocytic tumors, no cases showed widespread positivity for multiple histiocytic markers. Our results suggest that in relation to true histiomonocytic differentiation MFH might be a heterogeneous group of tumors. The widespread immunoreactivity for multiple histiocytic markers in some cases may indicate a true histiomonocytic differentiation in some MFHs.