Foraminifera as a model of eukaryotic genome dynamism.

In contrast to the canonical view that genomes cycle only between haploid and diploid states, many eukaryotes have dynamic genomes that change content throughout an individual's life cycle. However, the few detailed studies of microeukaryotic life cycles render our understanding of eukaryotic genome dynamism incomplete. Foraminifera (Rhizaria) are an ecologically important, yet understudied, clade of microbial eukaryotes with complex life cycles that include changes in ploidy and genome organization. Here, we apply fluorescence microscopy and image analysis techniques to over 2,800 nuclei in 110 cells to characterize the life cycle of Allogromia laticollaris strain Cold Spring Harbor (CSH), one of few cultivable foraminifera species. We show that haploidy and diploidy are brief moments in the A. laticollaris life cycle and that A. laticollaris nuclei endoreplicate up to 12,000 times the haploid genome size. We find that A. laticollaris reorganizes a highly endoreplicated nucleus into thousands of haploid genomes through a non-canonical mechanism called Zerfall, in which the nuclear envelope degrades and extrudes chromatin into the cytoplasm. Based on these findings, along with changes in nuclear architecture across the life cycle, we believe that A. laticollaris uses spatio-temporal mechanisms to delineate germline and somatic DNA within a single nucleus. The analyses here extend our understanding of the genome dynamics across the eukaryotic tree of life.IMPORTANCEIn traditional depictions of eukaryotes (i.e., cells with nuclei), life cycles alternate only between haploid and diploid phases, overlooking studies of diverse microeukaryotic lineages (e.g., amoebae, ciliates, and flagellates) that show dramatic variation in DNA content throughout their life cycles. Endoreplication of genomes enables cells to grow to large sizes and perhaps to also respond to changes in their environments. Few microeukaryotic life cycles have been studied in detail, which limits our understanding of how eukaryotes regulate and transmit their DNA across generations. Here, we use microscopy to study the life cycle of Allogromia laticollaris strain CSH, an early-diverging lineage within the Foraminifera (an ancient clade of predominantly marine amoebae). We show that DNA content changes significantly throughout their life cycle and further describe an unusual process called Zerfall, by which this species reorganizes a large nucleus with up to 12,000 genome copies into hundreds of small gametic nuclei, each with a single haploid genome. Our results are consistent with the idea that all eukaryotes demarcate germline DNA to pass on to offspring amidst more flexible somatic DNA and extend the known diversity of eukaryotic life cycles.

Effect of levamisole on malignant experimental neurinoma grown subcutaneously in a young rat: brief communication.

Levamisole, a drug that stimulates the immunologic defenses of the host, was tested on the experimental malignant neurinoma grown subcutaneously in young female inbred CDF rats in 3-month trial. The drug resulted in prevention of tumor growth in 80% of the treated animals, whereas tumors grew in 100% of the controls. After discontinuation of the drug, none of the animals in the treated group showed evidence of tumor growth upon clinical and pathologic examination 1 month after drug treatment was terminated. Treated animals failed to show any side effects related to levamisole upon clinical and pathologic examination.

Effect of levamisole on malignant experimental neurinoma grown subcutaneously in a young rat: brief communication.

Levamisole, a drug that stimulates the immunologic defenses of the host, was tested on the experimental malignant neurinoma grown subcutaneously in young female inbred CDF rats in a 3-month trial. The drug resulted in prevention of tumor growth in 80% of the treated animals, whereas tumors grew in 100% of the controls. After discontinuation of the drug, none of the animals in the treated group showed evidence of tumor growth upon clinical and pathologic examination 1 month after drug treatment was terminated. Treated animals failed to show any side effects related to levamisole upon clinical and pathologic examination.

Prevention of spontaneous tumors of aged mice by immunopharmacologic manipulation: study of immune antitumor mechanisms.

Effects produced by long-term application of three immune modifiers (azimexon, retinoic acid, and tuftsin) on the depressed immune systems of 18-month-old inbred C57BL/6 female mice were investigated. The effect of each agent was examined on four cell types (cytotoxic T-cells, K-cells, NK cells, and macrophages) possibly involved in antitumor defenses and on the spontaneous tumor development that accompanied advancing age. Three substances chosen for this study appeared able to alter immune parameters, and each one displayed its own pattern of activity. Common to all three agents were an increase of age-depressed tumoricidal activity of peritoneal macrophages and no effect on the depressed NK activity of spleen cells. Retinoic acid increased splenic K-cell activity, already elevated in aged mice and unaffected by the other two agents. Cytotoxic T-cell activity, diminished by age, was stimulated considerably by retinoic acid and by tuftsin but only slightly by azimexon. Histopathologic studies revealed a decrease in the incidence of spontaneous tumors in the 3 treated groups. This decrease was statistically significant in the retinoic acid- and tuftsin-treated groups when compared with the incidence in untreated mice of the same age. Correlation of drug-induced modifications of the immune system with tumor incidence in aged mice was attempted.

Diagnosis of fetal arrhythmias using echocardiographic and Doppler techniques.

Fetal echocardiography is the most practical method for diagnosing prenatal arrhythmias. Because some prenatal tachyarrhythmias have been shown to respond to antiarrhythmic drugs, correctly diagnosing fetal arrhythmias has assumed new importance. With the aid of two-dimensional echocardiographic imaging, an M-mode cursor can be aligned to record atrial and ventricular wall motion--either independently or simultaneously. A consistent feature in the fetus is prominent atrial wall contractions that can be readily recorded on the M-mode tracing. By matching atrial and ventricular wall contractions with assumed P waves and QRS complexes, the fetal electrocardiogram can be reconstructed. In 57 fetuses studied, recurrent atrial and ventricular ectopic beats were the most common prenatal arrhythmias. However, atrial flutter, ventricular tachycardia, atrial and ventricular bigeminy and atrial and ventricular bradyarrhythmias have been correctly identified and in some instances appropriately treated. Marked fetal bradycardia in the midtrimester of pregnancy is shown for the first time to be caused by transducer pressure on the maternal abdominal wall.

Diaminopurine-resistant mutants of cultured, diploid human fibroblasts.

Clones of cells resistant to 2,6-diaminopurine were detected in skin fibroblast cultures derived from 13 of 21 normal humans of both sexes from 17 unrelated families. Almost all of the cultures that yielded mutants were chosen for further study from among a total of 83 surveyed because they displayed a slight resistance to low concentrations of diaminopurine. The incidences of mutant colonies ranged between about 10(-5) and 10(-4) per cell surviving prior mutagenic treatment with MNNG. The incidences of spontaneous mutants were about 10(-7) to 10(-5) in three unrelated cultures. Most independent mutants had distinctly reduced activity of adenine phosphoribosyltransferase but some had apparently normal amounts of activity. Two mutants from unrelated boys had little or no detectable enzyme activity and were unable to effectively use exogenous adenine for growth when purine biosynthesis was blocked with azaserine. Most mutants could utilize exogenous adenine, just as most azaguanine-resistant fibroblast mutants can utilize exogenous hypoxanthine, even when their hypoxanthine-guanine phosphoribosyltransferase activity is reduced. Diverse genetic changes conferred diaminopurine resistance but their specific natures are still undefined. Gross numerical or structural chromosome abnormalities were not observed in the mutants examined so far. Since at least one gene responsible for adenine phosphoribosyltransferase activity is on autosome No. 16 our results suggest that at least some of the cultures yielding mutants were heterozygous and that alleles conferring diaminopurine resistance may be frequent enough to comprise a polymorphism.

Some acridine-resistant mutations of bacteriophage T4D.

Three new 9-aminoacridine (9AA) resistant mutations of bacteriophage T4D have been isolated and characterized. Two of the mutations, rs and rc, have identical patterns of acridine resistance, but they map on opposite sides of the rII region. In addition, rs has an effect on the plaque morphology of r mutations, whereas rc does not. The third mutation, ama, maps very close to rs but exhibits a different pattern of resistance to 9AA. None of the three is resistant to acridines by virtue of reduced permeability. Taken together with other mutations that have been previously characterized, these new mutations permit us to set the minimum number of acridine-sensitive processes in T4 development at four.

Studies of the bone marrow in polycythemia vera and the evolution of myelofibrosis and second hematologic malignancies.

The PVSG study is unique in that it is prospective and composed of 432 patients randomized to three treatment arms. This study also provides the opportunity for serial studies of numerous sequential biopsies. Large numbers of cases with sequential biopsies covering the entire long course are essential to appreciate the full spectrum of tissue changes in this disease. The PVSG was initiated in 1967 and in mid-1985 approximately one third of the patients are alive and on protocol. For these reasons, the results must still be considered preliminary. Pretreatment biopsies from patients randomized in the PVSG have been analyzed for total cellularity, megakaryocyte concentration, and reticulin content. Considerable variation in these elements was found in these biopsies. Sequential posttreatment biopsies from these patients have also been studied and correlated with the clinical course of the disease. None of the morphologic parameters analyzed was shown to be of prognostic significance. Early in the course of PV the marrow reticulin content is almost always normal. The length of the developmental stage is unknown and the precise timing of the clinical onset may be difficult. Therefore, the 11% of patients that showed a significant increase in reticulin on initial evaluation may have had PV longer than was indicated clinically. If large numbers of sequential biopsies are studied, an increase in reticulin content can frequently be demonstrated during the active phase of the disease and before the onset of the spent phase. Currently 39 patients (9%) have developed the spent phase, or PPMM. PPMM occurred in about the same incidence in the patients treated with myelosuppressive therapy as by phlebotomy alone, the spent phase occurring in 16 patients treated by phlebotomy alone, 11 with chlorambucil, and 12 with 32P. The course of the reticulin fibrosis is slowly progressive. There is some evidence for regression in a few patients in the erythrocytotic phase, but sampling variation cannot be completely ruled out. At this time in the study, AL has developed in 37 patients (8.6%). The incidence of AL is quite low in the phlebotomy group (three cases). Presumably this represents the natural incidence in PV unmodified by therapeutic agents. The frequency is approximately equal and quite high in the chlorambucil and 32P groups. There are 19 cases in the chlorambucil-treated group and 15 in the 32P-treated group. The leukemias that developed in the PV patients occurred either de novo or following PPMM.(ABSTRACT TRUNCATED AT 400 WORDS)

Atypical lymphoplasmacytic and immunoblastic proliferation in lymph nodes of patients with autoimmune disease (autoimmune-disease-associated lymphadenopathy).

This study is based on an analysis of the morphologic, clinical, and laboratory findings in 26 patients whose pretherapy lymph node biopsies showed some, but not all, of the diagnostic features of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD). Partial or complete effacement of nodal architecture by a diffuse lymphoplasmacytic and immunoblastic proliferation was a constant histologic finding. In contrast to the findings in AILD, lymphocytic depletion and pronounced arborizing vascular proliferation were often lacking. Clinically, many of the patients had fever, sweats, weight loss, skin rashes, generalized lymphadenopathy, hepatosplenomegaly, and, in some cases, pulmonary infiltrates. Of the 26 patients, 23 had clinical and/or laboratory evidence of autoimmune disease or immune complex disease. In 12 patients (Group I--idiopathic), various autoantibodies or immune complexes were demonstrable, but these patients did not manifest a well-defined immunologic disease or syndrome. In 11 patients (Group II--secondary), the lymphadenopathy occurred secondary to a well-defined, clinically recognized immunologic disease. Three patients (Group III) had neither a well-defined autoimmune disease nor demonstrable autoantibodies, but two of them had a history of exposure to antibiotics. We suggest that patients whose lymph nodes have the morphologic features described here frequently have an autoimmune disorder, and that the pathogenesis of this clinicopathologic picture is probably related to a deficiency in suppressor T-cell function which results in an unopposed proliferation of B cells with autoantibody formation and polyclonal gammopathy. Our observations should stimulate clinicians to consider the possibility of an autoimmune pathogenesis for a lymphadenopathy in which a florid lymphoplasmacytic and immunoblastic proliferation similar to that observed in AILD is demonstrated, even though the sections may not meet all the histologic criteria reported for the diagnosis of AILD. Clinical and laboratory investigations necessary to confirm the presence of autoimmunity are indicated in these cases. Moreover, since there is evidence of genetic factors predisposing to autoimmune disease (17, 43), it would be important to investigate close relatives of patients whose lymph nodes showed the histologic changes described in this paper in prospective studies which include suppressor T-cell function, autoantibodies, HLA type of blood lymphocytes and chromosomal analysis. The median survival of the 23 patients with stigmata of autoimmune disease or immune complex disease was 36 months.(ABSTRACT TRUNCATED AT 400 WORDS)

The diagnosis and differential diagnosis of hairy cell leukemia in bone marrow and spleen.

In this study we reviewed the morphologic features of marrow biopsies and aspirates as well as splenic sections derived from 28 patients with hairy cell leukemia. Marrow biopsies proved reliable in establishing and/or confirming the diagnosis in every patient, when available for review. Regardless of the degree of marrow involvement, the hairy cell infiltrates consistently exhibited wide spacing of their nuclei due to relatively abundant pale to clear cytoplasm. Hairy cells appeared homogeneous and bland, without mitotic activity or prominent nucleoli; nuclear contours characteristically were ovoid and to a lesser extent slightly indented or reniform. The splenic histology of hairy cell leukemia was equally distinctive. The splenic red pulp was diffusely infiltrated by a uniform population of cytologically monotonous mononuclear cells that expanded the red pulp cords, filled the sinuses, and generally led to atrophy or obliteration of the white pulp. Moreover, the clear cytoplasm of hairy cells usually was highlighted in sinusoidal blood-filled lakes. Despite the employment of these characteristic morphologic criteria for the diagnosis of hairy cell leukemia in marrow and spleen, these pathologic changes may vary and may be simulated in part by a variety of other hematologic disorders. Accuracy of diagnosis requires not only knowledge of the usual pathologic features of hairy cell leukemia but also knowledge of the unusual. Awareness of these pathologic variations will aid in the improvement of diagnosis and will provide a foundation for understanding the clinical and biologic aspects of hairy cell leukemia.

Whipple's disease of the lung.

Described here is a unique case of Whipple's disease in a 54 year old man with chronic severe cough and gastrointestinal symptoms in whom the initial diagnosis of Whipple's disease was made by lung biopsy. This is, to our knowledge, the first reported case in which the bacilliform structures of Whipple's disease have been demonstrated in tissues from other than the gastrointestinal tract of lymph nodes. Subsequently, a peroral biopsy of the small intestine was performed and revealed identical and pathognomonic features of Whipple's disease. The pulmonary roentgenologic findings are described and the histologic differential diagnosis of histiocytic infiltrates in the lung, which may be histologically similar to Whipple's disease, are briefly reviewed.

Angio-immunoblastic lymphadenopathy. Diagnosis and clinical course.

The clinical and pathologic findings in 24 patients with "angio-immunoblastic lymphadenopathy with dysproteinemia" (AILD) are presented. The patients' ages ranged from 44 to 80 years, with a median age of 68 years. The disease has an acute onset. In many respects, the clinical presentation is suggestive of malignant lymphoma. Generalized lymphadenopathy was always present. Hepatomegaly was found in 20 patients, splenomegaly in 17, constitutional symptoms in 20 and skin rashes in nine. Twenty patients had anemia, with positive Coombs' test in eight of 14 tested. Polyclonal hypergammaglobulinemia was found in 17 of 22 patients. Two patterns of evolution were recognizable: (1) long survival (24 to 67 months) without treatment or after the administration of intensive combination chemotherapy; and (2) rapid progression (one to 19 months) regardless of the treatment given. Sixteen patients died; postmortem examination in 10 cases showed the cause of death to be attributable to severe infection in eight patients, to renal disease in one and to cardiovascular disease in one. No evidence of malignant lymphoma was seen in any of these autopsies. Histologically, the disease is systemic, with specific lesions in the lymph nodes. The spleen, liver, bone marrow, skin and lung are also involved, but the changes are less characteristic than in the lymph nodes. In the patients in whom sequential biopsies were performed, a trend toward restoration of the nodal architecture was observed. AILD is a clinical-pathologic entity in a spectrum of yet to be defined immune reactions. The clinical, laboratory and pathologic manifestations of AILD are consistent with an autoimmune disorder, in which a deficiency of the T-cell regulatory functions probably predisposes to an abnormal proliferative and autoaggressive reaction of the B-cell system. Surgical staging procedures do not appear to be indicated. Intensive cytotoxic treatment may be hazardous in some patients, precipitating their death, but long survival after such therapy has been observed in others. Supportive therapy and small doses of steroids appear to be a safer therapeutic approach.

Legionnaires' disease.

Described here is a unique case of Legionnaires' disease in a previously healthy 46 year old man in whom disseminated disease was demonstrated in the kidneys, bone marrow, spleen and multiple peripheral lymph nodes at autopsy. The pathologic distribution of the lesions suggests that dissemination occurred by both hematogenous and lymphatic pathways. Pancytopenia associated with bone marrow destruction and fibrosis suggests that substances toxic to hematopoietic cells were present. It is likely that many of the unusual systemic manifestations of this disease are related to dissemination of the bacterium. The findings presented extend the spectrum of the clinical and pathologic manifestations of Legionnaires' disease from a mild and self-limited illness to a severe and fatal disseminated form of the disease.

Signet ring cell lymphoma. A rare morphologic and functional expression of nodular (follicular) lymphoma.

Nodular lymphomas and diffuse lymphomas of corresponding cellular composition have been shown to arise from follicular center cells. This paper describes a rare functional and morphological expression of malignant lymphomas arising from follicular center cells, namely, immunoglobulin production, an observation for which no detailed description or nanlysis is available in the literature. Furthermore, the unusual signet ring-like appearance of the lymphoma cells, which is due to retention of immunoglobulins within the cytoplasm, may result in an erroneous interpretation of metastatic adenocarcinoma or liposarcoma. Therefore, we are presenting a detailed analysis of light microscopic, histochemical, immunocytochemical, and ultrastructural observations. The lymphomas of all seven patients in our series showed nodular growth patterns; in all but one, diffuse areas were also observed. Five of the lymphomas were classified as poorly differentiated lymphocytic type and two as mixed cell type, according to Rappaport's classification. In four of the seven patients, the majority of the neoplastic cells had a clear vacuolated cytoplasm, and in three of these cases, a few of the neoplastic cells showed immunoperoxidase positivity for monoclonal IgG. This group in particular closely simulated metastatic carcinoma composed of so-called signet ring cells. In the remaining three cases, most of the neoplastic cells contained PAS-positive, Russell body-like monoclonal IgM. Ultrastructurally, the monoclonal IgG appeared as even-sized electron-dense spherules or irregular electron-dense clumps, while the monoclonal IgM appeared as membrane bound, homogeneous, electron-dense material. The implications of these findings and the morphologic features which are helpful in the identification of these lymphomas are discussed.

Non-Hodgkin's lymphoma involving the breast.

Breast involvement by non-Hodgkin's lymphoma is rare. Differences between primary and secondary breast lymphoma have been reported, and a relationship between primary breast lymphoma and lymphomas of mucosa-associated lymphoid tissue has been suggested. We reviewed 61 cases of breast lymphoma (41 primary, 13 secondary, and 7 unclear) that included 28 right-sided masses at presentation, 17 left-sided, 12 bilateral, and 4 in which the side was not known. A subgroup of bilateral breast lymphomas was identified that occurred in young women, four of which were pregnant or postpartum. A high incidence of intermediate- and high-grade lymphomas were present in both cases of primary and secondary lymphomas as was a high frequency of B-cell phenotype. Additional immunohistochemical studies failed to demonstrate evidence of marginal or mantle cell differentiation in seven of eight cases studied. Lymphoepithelial lesions were identified in a majority of cases, including 67% of primary and 64% of secondary lymphomas. This study failed to demonstrate a morphologic difference between primary or secondary lymphomas of the breast and suggests that breast lymphomas differ from other extranodal lymphomas in that the latter are frequently low grade.

Extramedullary myeloid cell tumors. An immunohistochemical and morphologic study of 28 cases.

In an attempt to correlate the morphologic and immunophenotypic findings in extramedullary myeloid cell tumors (EMT), we studied 28 cases with a large panel of antibodies using paraffin section immunohistochemistry. A previous or concurrent diagnosis of acute myelogenous leukemia or chronic myelogenous leukemia was made in 25 cases. Six EMT were morphologically classified as well differentiated (WD-EMT), 17 as poorly differentiated (PD-EMT), and five as blastic EMT. The WD-EMT were easily recognized morphologically and displayed a relatively mature myeloid phenotype, with elastase, CD15, and CD68 positivity in all cases. On the other hand, the five blastic-EMT displayed no morphologic evidence of myeloid derivation, were completely negative for CD15, and were weakly positive for elastase in only one case. The PD-EMT, with a morphologic appearance that resembles large cell non-Hodgkin's lymphoma, variably expressed CD15 and elastase. CD68 and lysozyme were present in the majority of PD-EMT, with some variability, but were negative in most blastic-EMT. CD45 (LCA) was detected in 75% of all EMT and CD34 was positive in 36%; neither antigen was significantly associated with a specific morphology. CD30 reactivity was not evident in any case, but slight positive staining was seen with CD20 (L26) in one WD-EMT. CD43 (Leu 22) was the only antibody that was positive in 100% of cases; staining was always intense and widespread. Antimyeloperoxidase (MPO) was positive in all cases but two, both with a blastic morphology. We conclude that (a) an immunohistochemical panel including CD20, CD43, CD68, and MPO can successfully identify the vast majority (96%) of EMT in paraffin sections, and (b) there is an association between morphology and phenotype in these lesions.

Leu-M1 antigen in human neoplasms. An immunohistologic study of 400 cases.

Several studies have shown that the Leu-M1 antigen, a monocyte/granulocyte-related marker, is consistently expressed by the neoplastic cells of patients with Hodgkin's disease (HD). It has been suggested that reactivity of Reed-Sternberg cells with Leu-M1 can be used in support of a morphologic interpretation of HD, and that it is helpful in the differential diagnosis of HD from morphologically similar lesions. To evaluate the significance of the Leu-M1 positivity of Reed-Sternberg cells in the diagnosis of HD, we investigated the distribution of Leu-M1 antigen in a series of patients with HD, non-Hodgkin's lymphomas, and nonhematopoietic neoplasms. We were able to demonstrate the presence of Leu-M1 antigen not only in the majority of patients with HD, but also in 12 of 18 (67%) peripheral T-cell lymphomas, as well as in a variety of nonhematopoietic neoplasms, which included 113 of 199 carcinomas, most of them (58%) adenocarcinomas. Only one of 34 sarcomas showed a focal positive reaction. Leu-M1-related antigen was not detected in any of 18 mesotheliomas, 15 germ cell tumors, 13 melanomas, three schwannomas, or three astrocytomas. Our study indicates that Leu-M1 positivity has no value in supporting the diagnosis of HD in situations where the histologic diagnosis of HD is doubtful. However, since anti-Leu-M1 reacted positively in the majority of adenocarcinomas but was absent in mesotheliomas, melanomas, and most sarcomas, this antigen could serve as a new marker that may be helpful in situations in which carcinoma is a part of the differential diagnosis.

Follicular small lymphocytic lymphoma.

We herein provide evidence for the existence of a distinct morphologic form of small lymphocytic lymphoma (SLL) that we term follicular small lymphocytic lymphoma (FSLL). Nine specimens of FSLL from eight patients were studied. The lymphomas in this study showed a true follicular pattern that was independent of tissue planes; the cytologic composition was identical to that seen in SLL. All six of the specimens (from five patients) for which paraffin tissue was available marked as B cell phenotype and were positive for bcl-2 protein. Polymerase chain reaction studies performed on deparaffinized tissue sections showed bcl-2 major breakpoint region rearrangements in four of five cases for which study tissue was available. Clinical information was available for all eight patients. All patients presented with lymph node disease, and three patients also had extranodal involvement at the time of presentation. Three of the patients had a relapse of disease after 33-95 months, and two of these patients died soon after relapse. Another two of the eight patients never responded to chemotherapy and died of their disease after 2 and 8 months, respectively. Two patients died of causes unrelated to their lymphoma and unrelated to any lymphoma therapy. Only one patient remains disease-free, after 65 months; this patient had a relapse at 44 months. The finding of bcl-2 rearrangements suggests that the pathogenesis of FSLL is more closely related to follicular small cleaved cell lymphoma than to classic SLL.

Distinction between undifferentiated (small noncleaved) and lymphoblastic lymphoma. An immunohistologic study on paraffin-embedded, fixed tissue sections.

The morphologic differentiation between malignant lymphoma of the small noncleaved cell (SNC) type and lymphoblastic lymphoma (LBL) is at times difficult, particularly when fresh tissue is not available for immunologic studies. We have examined the reactivities of a panel of monoclonal and polyclonal antibodies, including LN-1, LN-2, and antibodies to immunoglobulin light chains, leukocyte common antigen (LCA), Leu-M1, vimentin, S-100 protein, lysozyme, and alpha-1-antitrypsin, in paraffin-embedded, B5- and formalin-fixed tissue involved by SNC or LBL. The immunophenotypes in all of the cases included in this study had been characterized previously in fresh-frozen sections or cell suspensions. Among 21 samples of B5-fixed SNC, LN-1 was reactive in 17 and LN-2 in 18 cases. Among 13 B5-fixed LBL, LN-1 was reactive in two cases and LN-2 was reactive in two cases. Each of 20 B5-fixed samples of SNC was reactive with at least one of the antibodies, whereas 10 of the 13 B5-fixed samples of LBL were negative for both antibodies. Lesser reactivity was evident in formalin-fixed tissues, with only nine of 27 SNC specimens positive for LN-1 and 16 of 27 positive for LN-2. Most or all of the SNC and LBL samples were negative for immunoglobulin light chains, Leu-M1, vimentin, S-100 protein, lysozyme, and alpha-1-antitrypsin. The majority of both SNC and LBL were positive for LCA. We conclude that LN-1, preferably in combination with LN-2, can be used for distinguishing between SNC and LBL in paraffin-embedded, B5-fixed tissue when fresh tissue is not available.

True histiocytic malignancy associated with a malignant teratoma in a patient with 46XY gonadal dysgenesis.

The relatively frequent association of hematologic neoplasia and primary mediastinal germ cell tumors has been reported. Of these hematologic malignancies, nine were classified as malignant histiocytosis or acute monoblastic leukemia, and all occurred in males. We now report on a patient who was phenotypically female, with 46XY gonadal dysgenesis, and who developed a true histiocytic malignancy that presented as a large hepatic tumor and also involved the spleen, right kidney, and lymph nodes. Twenty-six months before the development of the histiocytic malignancy, an ovarian malignant teratoma with yolk sac elements was removed; the patient subsequently received chemotherapy. The neoplasm was composed of large pleomorphic cells and the histiocytic nature was established by cytologic, cytochemical, immunologic, and ultrastructural studies. In the course of her illness, the patient developed classic acute monoblastic leukemia 8 months after the diagnosis of histiocytic malignancy. Karyotypic analysis of the hepatic tumor, bone marrow, and blood showed 46XY gonadal dysgenesis. We believe that this is the first reported case of a phenotypically female patient who developed these two rare malignancies. It suggests that the association between germ cell tumors and histiocytic malignancy in genotypically male individuals may not be coincidental or secondary to therapy, but may be a phenomenon related to dysgenetic gonads in the presence of a Y chromosome.