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Patients with the inherited, bilateral form of retinoblastoma have an increased incidence of osteogenic sarcoma such that the mortality from the secondary tumor exceeds that of the initial bilateral retinoblastoma. We report a 29-year-old male survivor of bilateral retinoblastomas originally diagnosed at 8 months of age, whose treatment eventually included bilateral enucleation, bilateral orbital radiation, and systemic chemotherapy. At age 26, a tumor removed from his right maxillary sinus was diagnosed as fibroma. At age 29, he developed an inferior orbital mass that extended into the right maxillary sinus. A biopsy and comparison with the previous maxillary sinus mass revealed both lesions to be leiomyosarcoma. Both light and electron microscopy supported the diagnosis. The patient has survived treatment with orbital exenteration and maxillectomy combined with postoperative radiation to the right orbital-maxillary area. This appears to be the fourth case of leiomyosarcoma in the third decade of life in a male patient with a previously irradiated orbit after enucleation for bilateral retinoblastoma. Leiomyosarcoma appears to be another orbital tumor associated with bilateral retinoblastoma.

Microvillous lymphomas (MVLs) are rare, poorly defined, large transformed cell lymphomas characterized by a cohesive sinus growth pattern and ultrastructural cytoplasmic processes. Most MVLs express B-cell antigens and have been compared ultrastructurally to transformed follicular center cells and follicular dendritic cells. For additional definition of the immunophenotype of these unusual B-cell lymphomas, we evaluated eight cases of MVL for B-cell-associated antigens (CD21, CD35, CDw75, DBA.44, bcl-2) using paraffin immunoperoxidase. CD56, the neural cell adhesion molecule, was tested because of the unusual, cohesive, sinus pattern of tumor cell growth seen in MVL. Molecular analysis for immunoglobulin heavy chain and bcl-2 gene rearrangements was performed to confirm B-cell clonality and to evaluate cases for possible follicular origin. All of the cases were marked as B cells (CD20 positive), and the clonal nature confirmed by immunoperoxidase in five cases (63%) of eight and polymerase chain reaction for immunoglobulin heavy chain in seven cases (88%) of eight. CDw75 staining was present in six cases and CD74 in seven. DBA.44 and CD21 and CD35 were negative in all of the cases, and four cases (50%) of eight expressed CD56. bcl-2 protein expression was seen in seven of eight cases; bcl-2 gene rearrangement was present in one case (33%) of three studied. In conclusion, MVLs are B-cell lymphomas demonstrating clonal immunoglobulin heavy chain gene rearrangement. The neoplastic cells express CDw75 and bcl-2 protein. The presence of bcl-2 rearrangements in a limited number of cases implies that at least some MVLs have a follicular origin. Fifty percent of MVLs express CD56, suggesting a role for adhesion molecules in the distribution of this lymphoma.

Hepatosplenic gammadelta T cell lymphoma (TCL) is a rare, aggressive subset of peripheral TCL that presents with hepatosplenomegaly and cytopenias. Detailed clinicopathological, ultrastructural, and cytogenetic analyses of these lymphomas are limited; functional characteristics of these lymphomas are unknown. We have undertaken a clinicopathological, immunophenotypic, ultrastructural, cytogenetic, and functional analysis of three hepatosplenic gammadelta TCLs. All patients presented with massive hepatosplenomegaly and anemia, thrombocytopenia, or severe neutropenia; terminal blastlike transformation occurred in one patient. Combination chemotherapy had no response in two patients, but induced complete remission in one. gammadelta T cell receptor (TCR) expression and clonal TCRdelta gene rearrangements were documented in each case. Two different subsets of gammadelta TCL were identified based on delta chain variable region usage; two lymphomas were Vdelta1+, whereas the third was negative for both Vdelta1 and Vdelta2. Cytogenetic analysis was performed on two lymphomas; isochromosome 7q and probable trisomy 8 was shown in one of the Vdelta1+ lymphomas, whereas the Vdelta1 negative lymphoma had 14p+ with t(1;14)(q21;p13). NK cell-associated antigens (CD11c, CD16, or CD56) and cytotoxic T lymphocyte (CTL) effector proteins (perforin, granzyme B, TIA-1, and Fas ligand) were expressed by each lymphoma; dense core cytolytic granules were observed by electron microscopy in both lymphomas studied. Functional studies performed in two cases showed TCR-mediated cytolysis of P815 x 2 FcR+ cells induced by anti-CD3 in a redirected cytolysis assay in one of the CD56+, Vdelta1+ lymphomas, whereas IFNgamma secretion was induced by anti-CD3 in the CD56-, Vdelta1 negative lymphoma. These studies show that hepatosplenic gammadelta TCLs have CTL differentiation, retain functional activity in vitro, and are derived from at least two gammadelta T cell subsets.

The splenic marginal zone is a morphologically and perhaps immunologically distinct B-cell compartment. Lymphomas arising from cells of the splenic marginal zone are rare. Here we describe the morphologic, immunologic, and clinical features of 14 cases. Patient age ranged from 35 to 79 years (median, 68 years) with a male-to-female ratio of 1:1.8. The spleen was uniformly enlarged (median, 1,540 g; range, 388-3,845 g) in all patients, the neoplastic infiltrate had a nodular pattern in three cases, nodular and diffuse in seven cases, and diffuse in four cases. The neoplastic cells had small to medium-sized nuclei with round, oval, or slightly indented contours, small eosinophilic nucleoli, and a moderate amount of pale cytoplasm. Extrasplenic involvement was present in 12 patients. Lymph nodes often had a vaguely nodular pattern and preservation of sinuses; bone marrow was infiltrated focally (seven cases) or diffusely (one case). Five patients had hepatic involvement. Ultrastructurally, neoplastic cells differed from other small B cells and resembled normal marginal zone cells by having long, serpentine rough endoplasmic reticulum profiles. All lymphomas marked as B cells and light chain restriction was demonstrated in 12 cases. Bcl-2 protein expression was present in all cases. Most cases (70%) were negative for DBA.44 (CD72). Plasmacytic differentiation was present in three cases. In conclusion, splenic marginal zone lymphoma is a B-cell neoplasm with distinctive clinical, morphologic, immunologic, and ultrastructural characteristics.

The distribution of lesions of glomerulosclerosis, whether focal or diffuse, has important implications for pathogenesis and potential therapeutic response. Determination of focal or diffuse nature of lesions from a single section, may, however, be misleading. We therefore evaluated the distribution of segmental glomerulosclerosis in patients with nephrotic syndrome and idiopathic focal segmental glomerulosclerosis (FSGS) by three-dimensional analysis. From our files, we identified all such biopsies with a diagnosis established by immunofluorescence, electron microscopy, and light microscopy that had > 10 glomeruli and serum creatine < 3.5 g/dl. Renal biopsies from 15 adults (9 women, 6 men, age 40.3 +/- 4.2 years and six children (2 girls, 4 boys, age 6.3 +/- 1.4 years) thus identified had sufficient serial sections for analysis. An average of 20.0 +/- 2.6 glomeruli in adults versus 25.2 +/- 3.9 in children were examined. Sclerosis assessed on a single section involved 31.5 +/- 6.8% of glomeruli in adults, contrasting only 11.7 +/- 5.7% in children (P < 0.05). Complete serial section analysis was possible in 14.1 +/- 1.6 and 10.7 +/- 1.6 glomeruli in adults and children, respectively. After this serial section analysis, the percent of glomeruli involved by sclerosis increased to 48.0 +/- 6.6% in adults and 23.2 +/- 7.4% in children (P < 0.025). The pattern remained focal in all but one case that had the highest serum creatinine. The greater increase in sclerosis after serial section analysis in children versus adults reflects the predominance of small peripheral, that is, more segmental, lesions in children than adults.(ABSTRACT TRUNCATED AT 250 WORDS)

A 21-month-old boy presented with a papular rash, lymphoadenopathy, and splenomegaly. He developed symmetric polyarthritis, fever, and progressive glomerulonephritis. Serologies for viral agents including HIV were negative. Antinuclear antibody was transiently positive, but no anti-DNA antibodies were present. CH50 and serum C3 values were low. Biopsies of skin, kidney, bone marrow, and lymph node were obtained. There was a perivascular and periadnexal lymphocytic infiltrate in the skin, with a normal epidermis. Renal biopsy showed proliferative mesangial glomerulonephritis. Bone marrow showed an increased number of plasma cells. Lymph node showed histologic changes described in multicentric Castleman's disease including marked follicular hyperplasia, vascular proliferation, and interfollicular expansion with numerous plasma cells. IL-6 mRNA was demonstrated in cells in the marginal zone and interfollicular regions of the node by in situ hybridization. Likewise, the serum IL-6 level was elevated during a clinical exacerbation of the patient's nephritis. These data suggest an underlying lymphoproliferative disorder, such as Castleman's disease, with overproduction of IL-6 resulting in systemic features of the disease, including glomerulonephritis.

Marrow mast cells, frequently elevated in chronic B-lymphoproliferative disorders, were counted per high magnification field (HMF) on toluidine blue stained marrow biopsies from 34 patients diagnosed with hairy cell leukemia (HCL); similar counts were performed on splenic sections from nine of these patients. Biopsies from 28 normal marrow transplant donors and 10 normal spleens served as controls. Mast cells were distributed irregularly throughout normal and HCL marrows, but tended to be more concentrated about the hairy cells in cases focally involved by HCL. HCL marrows averaged 12.7 mast cells/HMF compared to 1.1 for controls. Although most normal marrows (86%) averaged < 2 mast cells/HMF, 88% of HCL cases averaged > or = 2 mast cells/HMF. Splenic mast cells averaged < 1/HMF for both HCL and control cases. By electron microscopy, marrow mast cells in HCL demonstrated normal substructure with numerous granules. The cell surfaces of mast cells showed filopodia that often came in contact with those of hairy cells. These results indicate most HCL marrows, but not spleens, are associated with varying degrees of mast cell hyperplasia. Furthermore, this study suggests a biologic interaction between mast cells and hairy cells. The significance of marrow mast cell hyperplasia in HCL is unknown, but these mast cells may contribute to the increased reticulin fiber network observed in HCL marrows.

A 35-year-old woman had a circumscribed pigmented scleral lesion overlying a pigmented mass in the ciliary body and trabecular meshwork. Sclerectomy and iridocyclectomy were performed. Histologically, the lesion proved to be a melanocytoma. This represents to our knowledge the fourth reported case of scleral extension of a ciliary body melanocytoma.

Thirteen cases of primary malignant lymphoma of the breast are reported from a 15-year retrospective review of records. The ages ranged from 19 to 75 years. One patient had nodular sclerosing Hodgkin's disease and 12 had non-Hodgkin's lymphoma. Eleven patients were treated with local excision, followed by radiotherapy, chemotherapy, or both. One patient had mastectomy and chemotherapy, and one had local excision only. Four patients died 6 months to 7 years after initial diagnosis. One patient was alive and with disease 5 years later. The remainder were alive and free of disease 24 months to 9 years after presentation. Prognosis depended on the clinical stage and histologic grade of the lesion. Five-year survival was 72 per cent, which was slightly better than that observed in mammary carcinoma.

We report a facial tumor that was proven to be a metastatic mesothelioma. The diagnosis was not established pre-mortem. The patient died shortly after the facial biopsy, and an autopsy revealed a large pleural-based mass which had the gross appearance typical of a mesothelioma. Electron microscopic examination of tissue from the pleural tumor was diagnostic for mesothelioma. The patient had extensive visceral metastatic disease. Inclusion of this entity in the differential diagnosis of certain cutaneous tumors is important, in part because this lesion may be confused with angiosarcoma, particularly when it occurs in the skin of the face or head in older patients.

The presence of type I collagen in both diffuse and nodular diabetic glomerular lesions has been examined using immunohistochemical and electron microscopic techniques. At the ultrastructural level, banded collagen fibrils were observed in the mesangium in all cases of nodular (Kimmelstiel-Wilson) sclerosis and in 60% of the diffuse sclerotic lesions. Antibodies against type I collagen were localized in the fibrotic interstitium and the mesangium in all cases examined. Staining with type I collagen antibodies occurred in glomeruli with intact Bowman's capsules, and was predominantly localized to areas immediately adjacent to mesangial cells. In cases of focal sclerosis of nondiabetic origin, banded collagen fibrils and staining with anti-type I collagen antibody were observed in all cases in which the segmental lesion was presented in the specimen. The pattern of antibody localization in both the diabetic lesions and focal sclerosis differed from that obtained using anti-type IV (basement membrane) collagen antibodies. These results demonstrate that type I collagen is among the extracellular matrix components that comprise the sclerotic glomerular lesions of both diabetic and nondiabetic origin. Furthermore, the spatial localization of this collagen type suggests mesangial cell origin.

Parafollicular (or monocytoid) B-cell lymphoma (PBCL) is a recently described low grade lymphoma. The relationship of parafollicular B cells to other B lymphocytes is not known, but the authors observed plasmacytic differentiation in the initial case of PBCL. In this report 12 cases of PBCL were studied by light microscopy and immunophenotypic analysis, and plasmacytic differentiation was found in four cases. This plasmacytic differentiation and the anatomic relationship of the neoplastic cells to reactive follicular centers suggest a functional relationship between these cell types.

Two unique, poorly-differentiated neuroepithelial tumors are described, one in a 35-year-old woman with an anterior mediastinal tumor and one in a 71-year-old woman with a left femoral mass. Immunocytochemical stains demonstrated Neuron specific enolase in both tumors and Chromogranin in one. Electron microscopy showed the cells of both neoplasms to contain abundant, thick, vermiform, organelle-free processes, previously described solely in large cell lymphomas. Rare dense-core granules were present, and very few processes were suggestive of neurites. These observations enlarge the spectrum of poorly differentiated neuroepithelial tumors.

Adenovirus (AV) infection usually has a benign course in normal hosts; however, in immunocompromised patients, AV may cause pneumonia, cystitis, or disseminated disease with substantial morbidity and even mortality. Although pulmonic AV involvement is common, infection of the kidney is unusual. The histologic findings previously described include tubular necrosis with interstitial inflammation and glomerulonephritis. We report a case of an AV-induced unilateral mass lesion in the kidney of a patient with Hodgkin's disease (HD) following bone marrow transplantation.

Anaplastic large-cell Ki-1 lymphoma is defined by its characteristic histological appearance, reactivity with antibodies against CD30, and possibly by a chromosome marker t(2;5)(p23;q35). Because of its pleomorphic appearance, sinus distribution, and frequent reactivity with EMA, this lymphoma is often mistaken for other diseases such as metastatic carcinoma and malignant histiocytosis. The clinical features of this lymphoma are unusual and include a young median age and frequent extranodal disease with skin being a common site. Although remission is easily achieved, relapse is common and combination chemotherapy is suggested. The role of Ki-1 antigen in normal lymphocyte function, the cell of origin of anaplastic large-cell Ki-1 lymphoma, and its relationship to Hodgkin's disease are important questions that hopefully will be answered in the near future.

Anaplastic large cell Ki-1 malignant lymphomas (MLs) resemble microvillous lymphoma in having a pleomorphic infiltrate with a prominent sinus growth pattern. Ultrastructural features of anaplastic large cell Ki-1 MLs and their immunologic relationship to the microvillous MLs have not been thoroughly evaluated. We have studied 23 anaplastic large cell Ki-1 MLs immunologically as well as 14 cases ultrastructurally, and compared them with 7 cases of microvillous MLs. Anaplastic large cell Ki-1 MLs were predominantly T-cell in type (13 cases) with three cases marking as B; in seven cases the immunophenotype was not clearly defined. Six microvillous MLs expressed monotypic cytoplasmic or surface immunoglobin and the remaining case had a probable B-cell phenotype (LN-1+, UCHL1-). All microvillous MLs were Ki-1/Ber-H2 (CD30) negative. Epithelial membrane antigen (EMA) marked most anaplastic large cell Ki-1 MLs, except those of B-cell type, whereas all microvillous MLs were EMA negative. By electron microscopy, both lymphomas had features of transformed lymphocytes although anaplastic large cell Ki-1 MLs generally had more nuclear irregularity and variability from cell to cell. Numerous cytoplasmic processes were present in three anaplastic large cell MLs and in all microvillous MLs. The ultrastructural features of the cytoplasmic projections were not sufficiently distinctive to differentiate these two lymphomas. It is apparent that at least two forms of MLs may have a sinus growth pattern and that these MLs cannot be differentiated by morphology alone. Full characterization requires a battery of immunological markers and ultrastructural studies; even then there is overlap of these MLs. The majority of microvillous MLs, are Ki-1-, EMA-, and have a B-cell phenotype, but a small population (21% in this study) of Ki-1+ MLs have numerous cytoplasmic processes. The biological and clinical significance of cytoplasmic projections in these lymphomas are unknown.

We report the occurrence of sterile corneal ulceration in 11 eyes of eight patients with collagen vascular diseases and dry eyes after cataract extraction with intraocular lens implantation. Keratolysis occurred after both extracapsular and intracapsular cataract extraction and appeared unrelated to the type of intraocular lens. Despite aggressive lubrication and other medical treatment, including systemic immunosuppressive agents, penetrating keratoplasty was often required. Although all eyes were saved, visual outcome was usually poor. The histopathologic finding of polymorphonuclear leukocytes localized near the areas of corneal dissolution provides evidence for the role of polymorphonuclear leukocyte-derived collagenase as a contributing factor in the pathogenesis of sterile corneal ulceration in these patients.

The study sought a diagnostic clue to identify the group of pediatric patients with apparent minimal change disease who subsequently develop focal glomerular sclerosis (FGS). Review of all renal biopsy material at our institutions identified 42 pediatric patients who met the standard criteria for minimal change disease (MCD) on initial biopsies. Of those, 10 deteriorated clinically and on rebiopsy showed focal glomerular sclerosis (FGS). The initial renal biopsies of these 10 patients were analyzed morphometrically to determine the mean glomerular tuft area (GA). The results were compared to those of the remaining 32 patients whose subsequent benign clinical course was consistent with MCD, and to randomly selected, age-matched autopsy controls without renal disease (CONT, N = 10). The mean age was comparable among the three groups studied. Separate groups of adult (N = 12) and pediatric (N = 18) patients with initial biopsies with FGS were also studied. The initial biopsy of pediatric patients who subsequently showed FGS (rebiopsy performed on average 3.3 years later) had an average GA of 13.5 x 10(-3) mm2, 76% larger than glomeruli from children with MCD (7.7 x 10(-3) mm2, P less than 0.0005) and 62% larger than CONT (8.4 x 10(-3) mm2, P less than 0.005). Patients with FGS on initial biopsy, whether adult or pediatric, also had significantly larger GA than the age-matched MCD or CONT groups. Evaluation of GA in all the 42 pediatric biopsies with initial MCD further showed that in 23 patients GA was equal to or smaller than the CONT average.(ABSTRACT TRUNCATED AT 250 WORDS)

To facilitate the direct study of the molecular events that control the development of human burst-forming units-erythroid (BFU-E), we have developed a method to purify BFU-E from peripheral blood. Using density centrifugation, rosetting with a mixture of neuraminidase-treated and IgG-coated sheep erythrocytes, positive panning with anti-My10 monoclonal antibody, overnight adherence to plastic dishes, negative panning with monoclonal antibodies, and density centrifugation, human blood BFU-E were purified from 0.04% to 56.6%, a 1,400-fold purification with a 13% yield. More than 90% of purified BFU-E were recombinant interleukin-3 (rIL-3) dependent, which survived for 48 h with rIL-3 in the absence of recombinant erythropoietin (rEP), and 80% gave rise to erythroid bursts of more than 500 hemoglobinized cells. rEP dependency was not evident until after 72 h of incubation in vitro. The purified cells (day 1) were incubated with rIL-3 and rEP in liquid culture for 24 (day 2), 48 (day 3), and 72 (day 4) h and then were transferred into semisolid cultures and incubated until day 15. The size of the erythroid colonies observed in semisolid cultures decreased continuously in association with the incubation time of day 1 purified cells in liquid cultures. The first appearance of colony-forming units-erythroid (CFU-E) that gave rise to colonies of 8 to 49 cells was observed after 72 h of incubation of day 1 cells in the liquid culture. 125I-rEP was incubated for 5 h at 37 degrees C with purified cells (day 1) or with the cells that had been incubated in liquid culture for an additional 24-72 h, and the presence of erythropoietin (EP) receptors was investigated using autoradiography. Specific binding of 125I-rEP was detected in 19 +/- 7% of the initial day 1 BFU-E. The percentage of 125I-rEP-binding to erythroid progenitor cells and the amount of binding continuously increased as day 1 BFU-E matured. 125I-rEP specific binding was observed with all of the erythroid progenitor cells that had been incubated in liquid culture for 72 h. These data demonstrate that primitive BFU-E have a much lower number of EP receptors than CFU-E and develop an increased concentration of EP receptors in association with their maturation and loss of proliferative capacity.

We report a 6-year-old white male with Laurence-Moon-Biedl syndrome and focal sclerosing glomerulonephritis (FSGN). To our knowledge, FSGN has not been reported previously in patients with this syndrome. We wish to alert the clinician to the wide variety of renal abnormalities that can be seen in patients with this rare, autosomal recessive disorder.

Basement membrane has been studied in vitro using human mammary lobules maintained in explant culture for periods up to 4 weeks. Morphologic similarities with basal lamina in malignant tumors in vivo have been observed, such as decrease in numbers of hemidesmosomes as determined by morphometry, reduplication and multilayering of the basal lamina, and failure to produce basal lamina after migration to the surface of the explant. Light microscopy using special stains for basement membrane has shown increasing fragmentation and loss with time in culture. These findings suggest that basement membrane changes seen in malignant tumors in vivo may not be limited to malignancy, per se, but may also be the result of other conditions.

The classification of acute leukemia is essential for proper therapy and may be based on morphologic, cytochemical, immunologic, or even ultrastructural studies. Terminal deoxynucleotidyl transferase (TdT) is expressed in most patients with acute lymphocytic leukemia (ALL) and a minority of patients with acute nonlymphocytic leukemia (ANLL). Thirteen patients with ANLL and greater than 30% blasts positive for TdT were studied to establish the clinical, light microscopic, cytochemical, immunologic, and ultrastructural correlates of this phenomenon. Most patients demonstrated some morphologic and cytochemical features of monocytic differentiation. On cytochemical stains, nine had greater than 3% Sudan black-positive blasts. Diffuse alpha naphthyl acetate esterase (ANAE) staining of leukemic cells was present in nine cases, though extremely weak in seven. Blasts in ten patients did not express any other markers of lymphoid differentiation except TdT. However, two patient's immature cells bore CD10 common ALL antigen (CALLA) and CD19 (B4). Ultrastructural studies confirmed nonlymphoid differentiation in all ten patients studied, with a prominent monocytic component present in nine. In no case was a second population of lymphoblasts identified to account for TdT positivity. These patients responded poorly to conventional therapy for ANLL, with complete remissions in 3 of 13 (23%). With conventional therapy for ALL, complete remission was achieved in only two of nine (22%) patients. However, four of seven (57%) patients had a complete remission with high-dose cytosine arabinoside regimens. The authors' studies suggest that patients with TdT-positive ANLL represent a distinct subset that usually displays ultrastructural evidence for monocytic differentiation and is clinically significant in that these patients respond poorly to conventional therapy for both ALL and ANLL. Recognition of the monocytic lineage of these cases by light microscopic examination is difficult because they are often poorly differentiated morphologically and express only weak nonspecific esterase positivity.

We studied 57 tumors of the thymus seen at Vanderbilt University Medical Center between 1957 and 1982. By applying current diagnostic criteria, the classification of 13 tumors was changed. There were 45 epithelial tumors of thymus, including 32 thymomas, two thymic carcinomas, eight carcinoids, and three germinomas. The gross and microscopic features of these neoplasms overlap each other and several other tumors, but with knowledge of the variations it was usually possible to establish a diagnosis with light microscopy. In more difficult cases, electron microscopy was the most useful diagnostic method. New developments in immunologic staining were also of value. The diagnosis of thymoma was used for circumscribed and invasive neoplasms of thymic epithelium without anaplasia. Cytologically malignant thymic epithelial tumors were classified as thymic carcinoma. Thymic carcinomas were more aggressive than thymomas and were not associated with syndromes such as myasthenia gravis or anemia. Thymic carcinoids were frequently aggressive, and several of them produced corticotrophin or calcitonin. Thymic germinomas were histologically identical to testicular seminoma, but may be confused with thymoma because of their lymphocytic infiltrate. Invasive germinomas were radiosensitive.

Tissues from malignant lymphomas with both nodular and diffuse growth patterns, thought by light microscopy to be composed of cells of follicular center cell (FCC) origin, Were examined by electron microscopy; the tumor cells were similar to lymphoid cells found in reactive follicular centers. Tumor cells from neoplasms thought to be composed of cleaved FCC often had more pronounced nuclear folding than did cleaved FCC of reactive follicles, whereas cells in tumors of noncleaved FCC type were indistinguishable from their presumed counterparts in reactive follicles. Large cell noeplasms, previously classified as "histiocytic" lymphomas were composed of cells with ultrastructural characteristics of transformed lymphocytes; they showed neither ultrastructural nor cytochemical features of mononuclear phagocytes. These findings support the concept that a major group of lymphomas arises from lymphocytes of follicular centers.

A 46-year-old man with a primary sarcoma of the pulmonary artery is presented. The tumor was responsive to radiotherapy, and the patient is the longest reported survivor of this rare disease. The tumor spread distally in the pulmonary vasculature, with probable embolization to the central nervous system, and he died 27 months after the initial diagnosis, with sudden massive hemoptysis. Pulmonary artery sarcomas are a rare cause of obstruction of the right ventricular outflow. The course of our patient suggests that early recognition and therapy may provide some of these patients with effective palliation and prolonged survival.

In order to identify the major clinical features and laboratory findings in patients with plasma cell iron, the authors reviewed the medical records and marrow aspirates of 53 consecutive patients with plasma cell iron hospitalized at Nashville Veterans Administration Hospital over a seven-year period. Plasma cell iron was associated most commonly with alcoholism and occurred in marrows with increased, normal, and decreased iron stores. In patients with decreased marrow iron, plasma cells were the major site of stainable iron. Plasma cell iron was found in patients without other morphologic changes of alcoholism such as megaloblastosis, erythroid vacuolization, and ringed sideroblasts. Plasma cell iron could be demonstrated in biopsy and autopsy material from extra-marrow sites. Ultrastructural studies showed iron always was located in membrane bound lysosomal vesicles of plasma cells.

Although follicular centers are the sites of production of plasma cell precursors, plasmacytic differentiation in follicular center cell (FCC) lymphomas is rarely seen, presumably because of a "block" in differentiation of the large noncleaved FCC. The authors reviewed a large number of these cases to determine the frequency of plasmacytic differentiation in FCC lymphomas. In one hundred ninety-eight, consecutive FCC lymphomas with a follicular pattern from a two-year period, 17 (9%) cases were found in which there were large numbers of plasma cells. Immunoperoxidase studies of paraffin-embedded sections (PIP) for cytoplasmic immunoglobulin showed polytypic marking in ten of these and a monotypic plasma cell population in seven. In this latter group, isotypically identical marking of the plasma cell and FCC populations could be demonstrated in three cases with immunoperoxidase (where the FCCs showed cytoplasmic marking) and in one case (of one tested) with surface typing studies. In addition, three patients had serum paraproteins identical to the plasma cell cytoplasmic immunoglobulins. These findings indicate that a small minority of FCC lymphomas contain sufficient plasma cells to be a diagnostic problem, and that in some of these cases, plasma cells are a differentiated component of the FCC lymphomas.

A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented.

A 52-year-old man with polycythemia vera of 20 years duration with progression to myelofibrosis developed a mass arising from the sternum. The mass consisted of large poorly differentiated cells infiltrating skeletal muscle, with cytochemical and ultrastructural features of malignant histiocytosis. At autopsy 6 weeks later, his bone marrow and spleen were involved by acute myelogenous leukemia. This is the first reported case of malignant histiocytosis occurring in a patient with polycythemia vera, and the second report of its association with acute myelogenous leukemia. There is suggestive evidence in this case that the malignant histiocytosis may possibly have arisen from the polycythemia vera clone.

The Mononuclear Phagocyte System, including promonocytes, monocytes, and tissue histiocytes (macrophages), gives rise to moncytic leukaemias and histiocytoses. A classification of these neoplasms by their presumed cell of origin is proposed, and criteria for their diagnosis are given. Histopathological, cytochemical, immunological and ultrastructural features useful in distinguishing these disorders form other haematopoietic or lymphoid neoplasms are presented in detail. The resulting classification reflects our knowledge at this time; as techniques become available to define further functional subpopulations of mononuclear phagocytes, it is likely that this classification will become as diverse as that of lymphoid neoplasms.

A 59-year-old man with no evidence or history of hyperlipidemia had a dystrophic xanthoma, an accumulation of lipid-rich foam cells in an area of damaged or abnormal skin, that was associated with untreated mycosis fungoides (MF). The patient was subsequently treated with whole-body electron beam therapy. This association of MF and dystrophic xanthoma illustrates histiocyte and xanthoma cell interaction in MF, a cutaneous T-cell lymphoma. Xanthomas may be a cutaneous sign of an underlying lymphoproliferative or myeloproliferative disease in normolipemic patients.

A 28 year old white women was found to have a cervical tumor in the 25th week of pregnancy. Pathologic examination revealed a nonkeratinizing small cell carcinoma. After delivery by cesarean section, pelvic lymph node exploration was carried out, and all 15 nodes were free of tumor. Her condition was staged as II-A, and she was treated with local radiation. Metastatic disease became manifest almost a year later and was histologically similar to her primary disease. A Cushingoid appearance was noticed and plasma cortisol levels were elevated. Twenty-four hour urinary 17-hydroxycorticosteroid (17-OHCS) and 17-ketosteroid (17-KS) levels were elevated and failed to suppress with dexamethasone. Plasma adrenocorticotropin (ACTH) level was elevated. Electron microscopic examination of the tumor tissue revealed neurosecretory granules. Immunoperoxidase stains for ACTH were positive. The patient's course was one of progressive decline and eventual death. A literature review revealed two other cases in which carcinoma of the uterine cervix was considered to be the source of ectopic ACTH. Some small cell carcinomas of the cervix may arise from cells of the APUD series. Small cell carcinoma of the uterine cervix may behave differently from the more commonly encountered keratinizing and large cell nonkeratinizing carcinomas of the cervix and may not respond as well to standard therapy. Ectopic hormone production, production of abnormal peptides or of vasoactive amines may be more common in small cell carcinoma of the cervix than is currently recognized, and these products may be clinically useful as tumor markers.

A case of mycosis fungoides in which pathologic rupture of the spleen led to intraperitoneal hemorrhage and death is described. To our knowledge, splenic rupture has not been reported previously as a cause of death in mycosis fungoides. Immunologic studies demonstrated that the neoplastic cell was a suppressor/cytotoxic T-cell. In most cases of mycosis fungoides or the Sézary syndrome, the neoplastic cell has been a helper/inducer T-cell. This case was very aggressive clinically with prominent visceral involvement and suggests that mycosis fungoides may be clinically diverse as well as immunologically heterogeneous.

A large renal tumor in a 7-month-old infant was composed entirely of lobules of clear cells with inactive nuclei. Electron microscopy demonstrated features indicative of origin from renal tubules. The infant remains well 15 months after resection.

"Sclerosis" is frequently seen in follicular center cell (FCC) lymphomas. The mechanism of its deposition, as well as its composition and significance, are unknown. Several clinical studies have suggested that the course of these lymphomas is more indolent than that of lymphomas of the same histologic type without sclerosis. Nine immunologically characterized cleaved FCC lymphomas with sclerosis and 14 reactive lymph nodes with follicular hyperplasia were investigated by special staining methods, electron microscopy, and immunohistochemical studies with antibodies to types I, III, IV, and V collagen, laminin, and fibronectin. The sclerotic tissue in FCC lymphomas stained uniformly with periodic acid-Schiff (PAS) and Masson's stain, with the patterns ranging from delicate filamentous strands to dense doubly refractile bands. Ultrastructurally, the bands of connective tissue were continuous with the adventitia of vessels and composed of varying amounts of banded collagen (types I and III) admixed with filamentous and flocculent material. In all cases the neoplastic lymphocytes were separated from the extra-cellular matrix by fibroblasts and myofibroblasts with long cell processes. Immunohistochemical studies demonstrated intense staining of sclerotic bands with antibodies to fibronectin and type I collagen and, usually, weaker marking with antibodies to types III and V collagen. No significant staining of sclerotic bands was found with antibodies to type IV collagen or with laminin. Weak pericellular staining for type V collagen was present in eight of nine lymphomas and half of the control lymph nodes. These studies suggest that the increased amounts of extracellular matrix in cleaved FCC lymphomas are produced primarily by fibroblasts and myofibroblasts and represent predominantly fibronectin and types I, III, and V collagen. The composition of the sclerotic areas of FCC lymphomas is similar immunohistochemically to that of the capsule and trabeculae of reactive lymph nodes, which are also intimately associated with fibroblasts and myofibroblasts.

Lymphomas with histologic features indicating a follicular center cell (FCC) origin were analyzed from 26 patients of a group of 45 consecutive non-Hodgkin's lymphoma patinets whose tumors were studied for B- and T-cell characteristics. They were compared with benign, reactive lymphoid tissue from 14 patients. Cell suspensions from biopsy material, blood, or bone marrow were examined for surface Ig and for rosette formation with sheep erythrocytes (E rosettes). Of the 26 patients with FCC lymphomas, 22 had 40% or more Ig-bearing cells; all patients with FCC lymphoma tissues had 25% or less E rosette-forming cells. Cells from most FCC lymphomas of the cleaved type had surfac IgM; those from several FCC lymphomas had both IgM and IgD. Cells from lymphomas of noncleaved cell type had surface IgG or IgA. Light-chain analysis showed that cells from FCC lymphomas bore a predominant light-chain type, which indicated their monoclonal nature. Neoplastic cells from several FCC lymphomas synthesized the surface Ig which they bore. Reactive tissues usually contained fewer Ig-bearing and more E rosette-forming cells than FCC lymphomas; the Ig-bearing cells, with one exception, had a polyclonal distribution. Correlation of histologic and immunologic observations indicates that most lymphomas identified as FCC in origin by light micorscopic criteria mark as B cells with the use of immunologic techniques and that FCC lymphomas are the most common type of non-Hodgkin's lymphoma.