Nonnasal lymphoma expressing the natural killer cell marker CD56: a clinicopathologic study of 49 cases of an uncommon aggressive neoplasm

Expression of the natural killer (NK) cell antigen CD56 is uncommon among lymphomas, and those that do are almost exclusively of non-B-cell lineage and show a predilection for the nasal and nasopharyngeal region. This study analyzes 49 cases of nonnasal CD56+ lymphomas, the largest series to date, to characterize the clinicopathologic spectrum of these rare neoplasms. All patients were Chinese. Four categories could be delineated. (1) Nasal-type NK/T cell lymphoma (n = 34) patients were adults 21 to 76 years of age (median, 50 years), including 25 men and 9 women. They presented with extranodal disease, usually in multiple sites. The commonest sites of involvement were skin, upper aerodigestive tract, testis, soft tissue, gastrointestinal tract, and spleen. Only 7 cases (21%) apparently had stage I disease. The neoplastic cells were often pleomorphic, with irregular nuclei and granular chromatin, and angiocentric growth was common. The characteristic immunophenotype was CD2+ CD3/Leu4- CD3epsilon+ CD56+, and 32 cases (94%) harbored Epstein-Barr virus (EBV). Follow-up information was available in 29 cases: 24 died at a median of 3.5 months; 3 were alive with relapse at 5 months to 2.5 years; and 2 were alive and well at 3 and 5 years, respectively. (2) Aggressive NK cell leukemia/lymphoma (n = 5) patients presented with hepatomegaly and blood/marrow involvement, sometimes accompanied by splenomegaly or lymphadenopathy. The neoplastic cells often had round nuclei and azurophilic granules in the pale cytoplasm. All cases exhibited an immunophenotype of CD2+ CD3/Leu4- CD56+ CD16- CD57- and all were EBV+. All of these patients died within 6 weeks. (3) In blastoid NK cell lymphoma (n = 2), the lymphoma cells resembled those of lymphoblastic or myeloid leukemia. One case studied for CD2 was negative and both cases were EBV-. One patient was alive with disease at 10 months and one was a recent case. (4) Other specific lymphoma types with CD56 expression (n = 8) included one case each of hepatosplenic gammadelta T-cell lymphoma and S100 protein+ T-cell lymphoproliferative disease and two cases each of T-chronic lymphocytic/prolymphocytic leukemia, lymphoblastic lymphoma, and true histiocytic lymphoma. All of these cases were EBV-. Six patients died at a median of 6.5 months. Nonnasal CD56+ lymphomas are heterogeneous, but all pursue a highly aggressive clinical course. The nasal-type NK/T-cell lymphoma and aggressive NK cell leukemia/lymphoma show distinctive clinicopathologic features and a very strong association with EBV. Blastoid NK cell lymphoma appears to be a different entity and shows no association with EBV.

Evaluation by magnetic resonance imaging of the inferior vena cava in patients with non-seminomatous germ cell tumours of the testis metastatic to the retroperitoneum

OBJECTIVE

To assess the role of magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in evaluating suspected occlusion of the inferior vena cava (i.v.c.) in patients with abdominal nodal metastases from non-seminomatous germ cell tumours, thus giving information that may be helpful in planning surgery and for determining the need for anticoagulant therapy.

PATIENTS AND METHODS

Five patients with abdominal nodal metastases in whom occlusion of the i.v.c. was suspected on computed tomography (CT) were imaged using a 1.5 T MRI scanner. The MRI findings were compared with those from CT.

RESULTS

The MR images successfully and clearly detected partial and total occlusions of the i.v.c. by both intraluminal thrombus and extrinsic compression. The technique also clearly detected extensive collateral venous circulation in several cases and in one a cavernous transformation of the i.v.c. In all patients, the MRI studies provided better information than that from CT.

CONCLUSION

MRI, and particularly MRA, is a comparatively new technique that is non-invasive and offers the potential of evaluating vascular structures with no need for ionizing radiation or contrast media. This technique, if available, should be chosen for imaging the i.v.c. in patients suspected of having compression or occlusion of the i.v.c.

Redefining the genital abnormality in the Robinow syndrome. -004

PURPOSE

We defined the anatomical structure of the male genital abnormality in the Robinow syndrome. Features of this syndrome include mesomelic brachymelia of the arms, bifid terminal phalanges of the hands and feet, characteristic facies, skeletal anomalies and hypoplastic external genitalia.

MATERIALS AND METHODS

Penile anatomy of 3 patients with the Robinow syndrome was assessed using computerized tomography and magnetic resonance imaging. Results were compared to those of 4 controls who underwent imaging for pelvic malignancies.

RESULTS

Cross-sectional imaging showed that normal penile crura were inserted onto the anteromedial aspect of the pubic bone. In contrast, in the Robinow syndrome they were inserted inferiorly and posteriorly onto the medial aspect of the ischial tuberosity. In addition, the crura in the Robinow syndrome extended posterior to a line intersecting both femoral shafts. Compared to controls, there was a significant gap between the symphysis pubis and dorsal aspect of the penis.

CONCLUSIONS

The penile anomaly in the Robinow syndrome is due to abnormal insertion of the penile crura, resulting in a penis that appears shorter and more inferiorly placed between the legs.

Validation of a high-performance liquid chromatographic assay method for pharmacokinetic evaluation of busulfan

The development and validation of a high-performance liquid chromatographic (HPLC) assay for determination of busulfan concentrations in human plasma for pharmacokinetic studies is described. Plasma samples containing busulfan and 1,6-bis(methanesulfonyloxy)hexane, and internal standard, were prepared by derivatization with sodium diethyldithiocarbamate (DDTC) followed by addition of methanol and extraction with ethyl acetate. The extract was dried under nitrogen and the samples reconstituted with 100 microl of methanol prior to HPLC determination. Chromatography was accomplished using a Waters NovaPak octadecylsilyl (ODS) (150 x 3.9 mm I.D.) analytical column, NovaPak ODS guard column, and mobile phase of methanol-water (80:20, v/v) at a flow-rate of 0.8 ml/min with UV detection at 251 nm. The limit of detection was 0.0200 microg/ml (signal-to-noise ratio of 6) with a limit of quantitation (LOQ) of 0.0600 microg/ml for busulfan in plasma. Calibration curves were linear from 0.0600 to 3.00 microg/ml in plasma (500 microl) using a 1/y weighting scheme. Precision of the assay, as represented by C.V. of the observed peak area ratio values, ranged from 4.41 to 13.5% (13.5% at LOQ). No day-to-day variability was observed in predicted concentration values and the bias was low for all concentrations evaluated (bias: 0 to 4.76%; LOQ: 2.91%). The mean derivatization and extraction yield observed for busulfan in plasma at 0.200, 1.20 and 2.00 microg/ml was 98.5% (range 93.4 to 107%). Plasma samples containing potential busulfan metabolites and co-administered drugs, which may be present in clinical samples, provided no response indicating this assay procedure is selective for busulfan. This method was used to analyze plasma concentrations following administration of a 1 mg/kg oral busulfan dose.

Combination of "patch, drain, and wait" and home total parenteral nutrition for midgut volvulus with massive ischemia/necrosis

The successful use of a combination of "patch, drain, and wait" (PDW) and home total parenteral nutrition (TPN) in the management of a case of acute, catastrophic midgut volvulus in a 2-year-11-month-old boy with near-total ischemia/necrosis of his small intestine is reported. The PDW approach to the highly effective management of acute midgut ischemia/necrosis in infancy and childhood (necrotizing enterocolitis and midgut volvulus) involves maximum gut salvage by avoidance of resection, stoma formation, or both through the use of extensive peritoneal cavity drainage by Penrose drains, TPN, and broad-spectrum antibiotics. The extensive peritoneal drainage fosters capture of enteric fistulas with the formation of enterostomies at drain exit sites, while adhesions and ischemia/inflammation-induced hypervascular obliteration of the peritoneal cavity diminish the potential for peritonitis (no peritoneal cavity, no peritonitis) and facilitate impressive salvage of seemingly hopelessly lost ischemic/necrotic gut (a simulation of the in utero ischemic gut process leading to atresias and some varying, but generally mild, gut loss) while simultaneously contributing to the resorption of absolutely non-salvageable gut and the creation of a remarkably clean and adhesion-free peritoneal cavity resembling that of a newborn infant with midgut intestinal atresia.

T- and T/natural killer-cell lymphomas of the salivary gland: a clinicopathologic, immunohistochemical and molecular study of six cases

Primary salivary gland lymphomas are almost always of B lineage, with most being represented by low grade B-cell lymphoma of mucosa-associated lymphoid tissue. This study characterizes the rare non-B-cell lymphomas of the salivary gland based on an analysis of six cases. All patients were men, with a mean age of 53.5 years. They presented with submandibular or parotid mass, which on histological examination showed extensive interstitial infiltration by small, medium-sized, or large lymphoid cells. There was prominent invasion and expansion of the ducts and acini in five cases. Angioinvasion was evident in two cases. Three cases were of T lineage and were CD56 negative; one of these cases expressed CD30. Three cases showed an immunophenotype of CD2+ CD3(f)- CD3(p)+ CD56+, consistent with T/natural killer (NK) cell lymphoma. In situ hybridization for Epstein-Barr virus (EBV)-encoded early nuclear RNA (EBER) showed positive reaction exclusively in the three CD56+ cases. Clonal T-cell populations were shown in two CD56-negative cases by polymerase chain reaction on paraffin sections using primers for the T-cell-receptor (TCR) gamma-chain gene, but not in the other four cases (the three CD56+ cases and one CD56- case). Four patients (two CD56+ and two CD56-) died within 3 years, and two were disease free at 4 and 1.5 years, respectively. This study shows that salivary gland T- or T/NK-cell lymphomas cannot be reliably distinguished from B-cell lymphomas on morphological grounds alone, because both can show prominent lymphoepithelial lesions. It appears that T/NK-cell lymphomas, which are often extranodal in localization and strongly associated with Epstein-Barr virus (EBV), show a predilection to involve the salivary glands as well.

Aggressive T/natural killer cell lymphoma presenting as testicular tumor

BACKGROUND

Nonnasal CD56+ T/natural killer (NK) cell lymphomas with morphologic and immunogenetic features similar to those of the distinctive nasal T/NK cell lymphoma are uncommon and have been characterized only recently. They show predominantly extranodal presentation, high stage disease, a highly aggressive course, strong association with Epstein-Barr virus (EBV), and lack of T cell receptor gene rearrangement. Only one previously reported case had a testicular presentation, although the testis is not uncommonly involved during the course of disease in both nasal and nonnasal T/NK cell lymphomas.

METHODS

Three patients with T/NK cell lymphoma who presented initially with a testicular mass are reported.

RESULTS

The three patients underwent orchidectomy for testicular tumor. Histologically, the testes showed diffuse dense infiltration of medium-sized or large lymphoma cells. Antiocentric growth and necrosis were prominent in two cases. The lymphoma had the following immunophenotype: CD2+ CD3 epsilon+ CD56+ compatible with T/NK cell lymphoma; two lacked staining with Leu4 (CD3), and one had weak staining. With immunohistochemical preparations, it was noted that the rete testis stained consistently for CD56, and the Leydig cells and Sertoli cells showed patchy staining. The neoplastic cells harbored EBV, as demonstrated by in-situ hybridization. Additional sites of disease were detected at the time of the diagnosis in one patient (nose) or appeared soon afterwards in all three patients (skin or gastrointestinal tract). All three patients died within 5 months.

CONCLUSIONS

This study confirms that testicular CD56+ T/NK cell lymphoma tends to disseminate early, pursues an aggressive course, and is strongly associated with EBV. CD56 recognizes the neural cell adhesion molecule (NCAM), which exhibits homophilic binding properties. The expression of CD56 in the normal testicular constituents can perhaps explain the tendency for T/NK cell lymphoma to localize in this organ.

Utility of a paraffin section-reactive CD56 antibody (123C3) for characterization and diagnosis of lymphomas

Although expression of CD56 (neural cell adhesion molecule, a natural killer cell marker) is uncommon among lymphomas, this feature has defined a distinctive and important category of lymphoma: the putative natural killer (NK) cell lymphoma, which shows a predilection for the upper aerodigestive tract, skin, skeletal muscle, and other extranodal sites and pursues an aggressive clinical course. Thus far, CD56 expression can be reliably analyzed only on fresh or frozen tissues. In this study, we evaluated the sensitivity and specificity of a CD56 antibody, 123C3, when applied on routine formalin-fixed, paraffin-embedded tissues for analysis of lymphomas, by comparing the staining results with those obtained on frozen tissues using the CD56 antibody NKH1. The 123C3 antibody worked on paraffin sections only with prior antigen retrieval using a pressure cooker or a microwave oven. Among 32 CD56+ T/NK cell lymphomas and one CD56+ B-lymphoblastic lymphoma, the neoplastic cells showed crisp membrane staining with 123C3 in all cases. None of the 24 CD56- T-cell lymphomas and 50 CD56-B-cell lymphomas stained with 123C3. In normal or reactive lymphoid tissues from a variety of sites, there were few small lymphocytes (< 0.1%) that showed cell membrane staining with 123C3, although occasional plasma cells might show cytoplasmic staining. We conclude that with suitable antigen retrieval procedures, 123C3 can be reliably applied on routine paraffin sections for detection of CD56 expression in lymphomas. Furthermore, this antibody can be used to support a diagnosis of lymphoma or to detect residual disease for cases of CD56+ T/NK cell lymphoma in which the neoplastic lymphoid cells are small and show minimal atypia, especially in small biopsies.

Hepatosplenic gamma delta T-cell lymphoma. A distinctive aggressive lymphoma type

The T-cell receptor (TCR) expressed on the surface of most T-lymphocytes is of alpha beta type, and only a minority bear the gamma delta-TCR. Similarly, postthymic T-cell lymphomas rarely express gamma delta-TCR. Hepatosplenic gamma delta T-cell lymphoma is an uncommon entity that has so far not been widely recognized. We report one such case that has been comprehensively studied by multiple modalities and showed the unique occurrence of leukemic picture at presentation. The 39-year-old man presented with fever, marked weight loss, and massive splenomegaly. Peripheral blood showed thrombocytopenia and a white cell count of 5.8 x 10(9)/l, with 66% medium-sized lymphoid cells that had a round or folded nucleus, condensed chromatin and a moderate amount of pale blue cytoplasm. Splenectomy was performed and histologic examination of the spleen, bone marrow, liver, and abdominal lymph nodes demonstrated lymphoma infiltration with a predominantly sinusoidal pattern. Immunohistochemical studies of the lymphoma cells showed a T-cell phenotype: CD2+ CD3+ CD5+ CD7+ gamma delta-TCR+ alpha beta-TCR- CD56+ CD4- CD8- CD16- CD57-. Cytogenetic studies showed complex clonal chromosomal abnormalities of 44,X, -Y, -11, -22, + mar in 3/16 cells. Rearrangement of the TCR gamma chain gene was demonstrated by polymerase chain reaction; the TCR beta chain gene was partially chain reaction; the TCR beta chain gene was partially rearranged. The patient did not respond to single agent chemotherapy, but achieved clinical remission with combination chemotherapy. Based on the available data in the literature, hepatosplenic gamma delta T-cell lymphoma exhibits distinctive clinicopathologic features, and probably represents the neoplastic counterpart of splenic gamma delta T-lymphocytes. This disease is associated with a poor prognosis and usually relapses despite initial response to chemotherapy.

A study of the association of Epstein-Barr virus with Burkitt's lymphoma occurring in a Chinese population

There is a strong association (approximately 95%) of endemic Burkitt's lymphoma with Epstein-Barr virus (EBV), whereas the association is weak for the sporadic form occurring in Western countries (approximately 15%). In the Middle East, North Africa and South America, 60-80% of Burkitt's lymphomas harbour EBV. These epidemiological differences suggest that either the endemicity of EBV or socio-economic conditions, or both, may influence the pathogenetic role of EBV in Burkitt's lymphoma. Since only meagre data are available on Asians, this study was performed to address this issue by studying cases from Hong Kong, where EBV seroconversion occurs in the first few years of life but the socio-economic conditions approach those of Western countries. In situ hybridization for EBV encoded RNAs (EBERs) was performed on paraffin sections of 18 cases of Burkitt's lymphoma. Labelling of the neoplastic cells was detected in five cases (27.7%). In contrast, among 54 cases of B-cell lymphomas of various subtypes studied for comparison, signals for EBER were detected in only one case each of T-cell-rich large B-cell lymphoma, anaplastic large cell lymphoma and Reed-Sternberg-like cells occurring in B-cell chronic lymphocytic leukaemia/small lymphocytic lymphoma. The strong labelling with oligo-dT probe (which hybridized with the polyadenylated ends of mRNA) in all cases suggested that the negative results were genuine and not due to poor preservation of RNA in the tissues. Thus, among B-cell neoplasms occurring in Chinese, Burkitt's lymphoma shows a statistically stronger association (P < 0.01) with EBV than with other types of B-cell lymphoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Coccoid forms of Helicobacter pylori in the human stomach

Helicobacter pylori (HP) may transform from helical bacillary forms to coccoid forms after several days' in vitro incubation. The authors examined 111 consecutive gastrectomy specimens for the presence of coccoid forms of H pylori. Tissues from 64 stomachs (57.7%) showed colonization by H pylori, including 49 cases (76.6%) of adenocarcinoma, 14 cases (21.9%) of benign peptic ulcer, and 1 case (1.6%) of malignant lymphoma. Of these, coccoid forms of H pylori were identified in 53 cases (82.8%). In hematoxylin-and-eosin-stained sections coccoid forms of H pylori appeared as solid, round, basophilic dotlike structures. Under an electron microscope, coccoid forms of H pylori appeared as U-shaped bacilli, with the ends of the two arms joined by a membranous structure. Ultrastructural findings were identical to those from cultures of H pylori. With anti-Helicobacter antibody, coccoid forms of H pylori were positively stained by immunoperoxidase. Helical bacillary forms of H pylori invariably coexisted with the coccoid forms. By semiquantitative analysis, the number of coccoid forms in adenocarcinoma was significantly (P > .01) greater than that in benign peptic ulcers. This study confirms that H pylori can exist in coccoid forms in the human stomach. Coccoid forms should be distinguished from the pathogenic or nonpathogenic bacterial cocci, fungal spores, and cryptosporidia that may colonize the human stomach.

Epstein-Barr virus-associated gastric lymphoma in Hong Kong Chinese

We report 11 cases of gastric lymphoma that harbor the Epstein-Barr virus (EBV) encoded small messenger RNA, EBER-1, detected by in situ hybridization. The cases represented 18% of 61 consecutive gastric lymphomas from three institutions in Hong Kong between 1988 and 1993. The mean age of patients was 62 years (range, 33 to 87). The male to female ratio was 5:6. Nine of the 11 (81.8%) EBER-1+ gastric lymphomas were diffuse large cell lymphomas of B-cell type without low grade components. Macroscopically these lymphomas appeared either as large noncleaved cell (centroblastic) or immunoblastic type. From the available follow-up data, five of the nine patients with B-cell lymphoma were alive and well 48, 40, 14, 13, and 12 months, respectively, after gastrectomy and chemotherapy. One patient died of postoperative pneumonia and one died of a second malignancy (esophageal squamous carcinoma) 40 months after gastrectomy. None of the EBER-1+ B-cell gastric lymphomas showed histological features characteristic of low grade lymphoma of the mucosa-associated lymphoid tissue (MALT) type reported to be common in some Western countries. Of the two patients with T-cell lymphoma, one had a pleomorphic T-cell lymphoma and the other had an angiocentric lymphoma. The former was lost to follow-up after the biopsy and the latter presented with gastric perforation and died 1.5 months after gastrectomy. It is concluded that a significant proportion of gastric lymphomas in Hong Kong Chinese are EBV-related and that they show histological features more akin to conventional node-based lymphomas than to MALT-type lymphomas.

Detection of Epstein-Barr viral RNA in malignant lymphomas of the upper aerodigestive tract

Recent studies have suggested a probable etiologic association between Epstein-Barr virus (EBV) and nasal lymphomas, irrespective of geographic location. This study was performed to investigate the strength of association of EBV with non-Hodgkin's lymphomas of the upper aerodigestive tract, based on a large series of cases that have been thoroughly immunophenotyped on frozen tissues. A sensitive in situ hybridization technique was used to detect EBV encoded RNA (EBER) in paraffin sections. Among 30 cases of nasal/nasopharyngeal T-cell lymphoma, 25 (83.3%) were EBER-positive. In the positive cases, most of the neoplastic cells showed strong nuclear signals. Further analysis of this group of tumors showed that all 21 cases (100%) with a CD56+ CD3-phenotype were EBER positive, whereas four of nine cases (44.4%) with a CD56-negative immunophenotype were positive. Only one of 10 cases (10%) of nasal/nasopharyngeal B-cell lymphoma was EBER positive; the positive case was a diffuse mixed-cell lymphoma and could not be distinguished morphologically from the negative cases. Among the 21 cases of lymphoma of the tonsils and back of the tongue (20 B-lineage and one T-lineage), none was EBER positive. In the normal mucosa of the nose/nasopharynx or tonsil (20 cases studied), only very rare EBER-positive small lymphocytes were found in two cases. The almost exclusive detection of EBER in nasal/nasopharyngeal T-cell neoplasms among the lymphomas of the upper aerodigestive tract suggests that EBV probably plays an etiologic role in the pathogenesis of this group of tumors and is not simply a passenger virus, and neither is this merely a site-dependent phenomenon in view of the weak association with nasal/nasopharyngeal B-cell lymphoma.

In situ localization of Epstein-Barr virus encoded RNA in non-nasal/nasopharyngeal CD56-positive and CD56-negative T-cell lymphomas

We recently reported a group of non-nasal/nasopharyngeal hematolymphoid malignancies expressing the natural killer cell marker CD56, characterized by frequent extranodal localization, angiocentricity, and aggressive clinical course (HUM PATHOL 23:798-804, 1992). Because we have shown a very strong association of Epstein-Barr virus (EBV) with CD56-positive T-cell lymphomas of the nose nasopharynx, we asked whether a similar association also occurs with the non-nasal CD56-positive T-cell lymphomas. In situ localization of EBV encoded RNA (EBER) was performed on paraffin sections of 15 such cases, including the nine previously reported cases and six new cases (three showing prominent hepatosplenic involvement and three showing involvement of one or more extranodal sites, such as the parotid gland, tonsils, gastrointestinal tract, skeletal muscle, and testis). A case was considered positive when the majority of the tumor cells showed nuclear signal. Ten cases showed EBER positivity, and all but one of them were negative for CD3 and other T-cell markers, except CD2. Only one of four cases showing a CD3-positive phenotype was EBER positive. Of the remaining two CD3-negative EBER-negative cases, one showed a histiocytic phenotype and the other was positive for multiple T-cell markers. Among 15 cases of CD56-negative non-nasal peripheral T-cell lymphoma studied for comparison, six were CD3-negative, among which three showed EBER positivity. All nine CD3-positive cases were EBER negative. Five cases (three CD3 positive and two CD3 negative) showed rare isolated (< 1%) EBER-positive tumor cells. We conclude that among non-nasal T-cell lymphomas, EBV is strongly correlated with CD56 positivity (66.7% v 20%), and the positive cases almost always show an immunophenotype identical to that commonly observed in nasal lymphomas (CD2 positive, CD3 negative, and CD56 positive). Thus, EBV may play an etiologic role in these CD56-positive lymphomas. There is also a correlation between EBER positivity and CD3 negativity, irrespective of the CD56 status. The presence of isolated EBER-positive cells in CD56-negative T-cell lymphomas, occurring at a frequency similar to that reported in the European population, probably represents secondary infection of tumor cells.

CD56 (NCAM)-positive malignant lymphoma

CD56, a natural killer cell marker reactive with the neuronal-cell adhesion molecule (NCAM), identifies a group of lymphomas with distinctive clinicopathologic features. The disease affects mostly middle-aged adults who often present with fever, skin rash and hepatosplenomegaly in the absence of peripheral lymphadenopathy. Extranodal involvement is common, particularly the skin, aerodigestive tract and central nervous system. Histologically, an angiocentric and angiodestructive pattern of infiltrate is often seen, but the cytological spectrum of the lymphoma cells is very broad. Cytoplasmic granules, however, are frequently found when Giemsa-stained cytologic preparations are examined. Immunologically, CD56-positive lymphomas can be sub-classified into CD3-positive (T-cell) and CD3-negative (probably true natural killer cell) subtypes. T-cell receptor gene rearrangement can be demonstrated in the former cases, but not in the latter. Clinically, CD56-positive lymphomas are aggressive neoplasms.

Follicular dendritic cell tumor and vascular neoplasm complicating hyaline-vascular Castleman's disease

The localized form of hyaline-vascular Castleman's disease may rarely be complicated by a vascular neoplasm, which appears to arise in a background of vascular hyperplasia. We report a case complicated by follicular dendritic cell tumor, a hitherto undescribed occurrence that is expected from the presence of a "dysplastic" component of follicular dendritic cells in Castleman's disease. The patient had a large tumor mass in the mesocolon, associated with multiple small peritoneal deposits. The lesion showed typical histologic features of follicular dendritic cell tumor with storiform arrangement of spindly cells and admixture of small lymphocytes. The follicular dendritic cell nature of the tumor was confirmed by immunoreactivity with CD21 and CD35 antibodies and by ultrastructural demonstration of cell processes connected by desmosomes. Hyaline-vascular follicles were identified at the peripheral portion or occasionally scattered in the center of the tumor. Rarely, follicle-like structures were formed by tumor cells, possibly representing in situ malignant change. In addition, there was a small focus of vascular neoplasm comprising well-formed pericyte-rich small blood vessels devoid of cellular atypia. This report of the development of follicular dendritic cell tumor in Castleman's disease therefore completes the picture in that tumors corresponding to each cell type that proliferates in Castleman's disease have now been documented.

Nodular desmoplastic variant of trichoblastoma

A case of an unusual, previously unreported, nodular desmoplastic variant of trichoblastoma (hair germ neoplasm) in the scalp of a 65-year-old woman is reported. Four discrete nodules were present in close proximity at presentation. Another nodule developed in the same vicinity 3 1/2 years after excision, and there was no further recurrence 2 1/2 years later. The tumors were located in the dermis, made up of cords of primitive hair germ-like structures radiating down from discrete hyalinized nodules located in the superficial dermis. There were small foci of keratinization or mucoid change within the epithelial islands. Toward the deep portion of the tumor, the epithelial cells became spindly and grew in a more dispersed pattern, within a desmoplastic stroma. There was also infiltration of the epineurium of the cutaneous nerves and arector pili muscle. This uncommon benign neoplasm of hair germ merits wider recognition; in particular, this desmoplastic variant may mimic invasive carcinoma, morphea-type basal cell carcinoma, desmoplastic trichoepithelioma, and desmoplastic trichilemmoma. Distinguishing this variant from the former two possibilities is particularly important in order to avoid unduly aggressive treatment.

Odorant binding by a pheromone binding protein: active site mapping by photoaffinity labeling

The bacterially expressed recombinant pheromone binding protein (PBP) of Antheraea polyphemus was photoaffinity labeled with (6E,11Z)-[3H]hexadecadienyl diazoacetate, a photoactivatable analog of the naturally occurring acetate pheromone. Radiolabeled peptides were separated from an endoproteinase Lys-C digestion by HPLC and characterized by Edman degradation. The label was exclusively found in the Asp39-Lys58 fragment. Cleavage of this peptide (DDYVMTDRLAGCAINCLATK) with Arg-C gave a single radiolabeled peptide (DDYVMTDR), which was predicted to be alpha-helical. The adjoining LAGCAINCLATK fragment, which is highly conserved in PBP sequences, was predicted to be a hydrophobic beta-strand and has been proposed to be important in recognition of the alkadienyl chain. Edman degradation confirmed the location of the covalently attached ligand at Thr44 of the smaller hydrophilic peptide. In addition, the synthesis of the newly identified pheromone component (4E,9Z)-tetradecadienyl acetate and its photoaffinity analog, (4E,9Z)-[3H]tetradecadienyl diazoacetate, is also described. Mapping of PBP photoaffinity labeled by (4E,9Z)-[3H]14:Dza revealed that the hydrophobic region Asp21-Lys38 adjacent to the primary binding domain Asp39-Lys58 contained a second modification site. The 14-carbon odorant molecule thus had two binding positions within the recognition site, while only a single binding position was available to the 16-carbon pheromone.

Kikuchi's lymphadenitis. A morphologic analysis of 75 cases with special reference to unusual features

Seventy-five cases of Kikuchi's lymphadenitis, a self-limiting pseudomalignant condition, were reviewed to determine the spectrum of histologic findings. There were 55 females and 20 males; ages ranged from 9 to 57 years (mean, 25.5). Most patients presented with cervical lymphadenopathy (68 cases). Associated clinical findings were fever (20/52) and leukopenia (15/33). Serum antinuclear antibodies were negative in 15 patients among 16 tested. Among 32 patients with follow-up information, 31 remained well, including one who developed recurrence after 2 years. One patient died of fatal myocardial disease during the active disease. Histologically, the lymph nodes showed paracortical hyperplasia, often associated with a starry-sky appearance resulting from interspersed histiocytes and immunoblasts. The consistent finding was the presence of variable-sized discrete or confluent nodules in the paracortex composed of the following: (a) karyorrhectic and eosinophilic granular debris; (b) histiocytes, many of which were phagocytic and possessed distinctive peripherally placed crescentic nuclei and voluminous cytoplasm containing eosinophilic or karyorrhectic debris (for which we propose the designation crescentic histiocytes), mixed with nonphagocytic histiocytes having twisted or reniform nuclei which were often centrally placed; (c) plasmacytoid monocytes, which were medium-sized cells with eccentrically placed round nuclei and amphophilic cytoplasm; and (d) variable numbers of immunoblasts, which sometimes showed atypia such as irregular nuclear foldings and coarse chromatin. Neutrophils were absent or very sparse. In some nodules, coagulative necrosis was present in the center (45 cases). Foamy histiocytes were found in 23 cases, and they predominated in 11. Small clusters of plasmacytoid monocytes were noted in the paracortex in 40 cases. Perinodal inflammation was a common finding, and perinodal involvement by the karyorrhectic process occurred in 15 cases. In addition, we found a number of previously unreported features. Signet-ring histiocytes with clear or homogeneous lightly amphophilic cytoplasm and nuclei compressed into thin crescents, found in seven cases, could mimic signet-ring cell adenocarcinoma. In three cases, some germinal centers were involved by the karyorrhectic process. Foci of lymphocyte-depleted fibrovascular organization were present in eight cases, probably representing the resolving phase of the karyorrhectic process. Despite the broad morphologic spectrum, the intermingling of the distinctive crescentic histiocytes, karyorrhectic debris, and plasmacytoid monocytes in the form of nodules, together with the paucity of neutrophils, are the consistent findings that should permit a confident histologic diagnosis of Kikuchi's lymphadenitis.

Follicular dendritic cell tumors of the oral cavity

Follicular dendritic cell tumors are uncommon, and all the reported cases have occurred as primary lymph node tumors. We report two cases in the oral cavity, one in the soft palate and one in the tonsil. The tumors were characterized by sheets, whorls, and storiform arrays of spindly and syncytial-appearing cells with oval nuclei, fine chromatin, distinct nucleoli, and occasional nuclear pseudoinclusions. Multinucleated forms were present and were prominent in one case. An unusual feature was the presence of irregular pseudovascular spaces, which could raise a concern for vascular neoplasm. Because the tumors showed cohesive growth and a sharp interface with the fibrous stroma, they could also be mistaken for carcinoma, sarcoma, or melanoma. After radiation therapy, the palatal tumor showed a greater degree of nuclear pleomorphism, numerous nuclear pseudoinclusions, and striking nuclear grooving and foldings, mimicking interdigitating reticulum cell tumors. The diagnosis in both cases was confirmed by immunoreactivity with CD21 and CD35 and by ultrastructural demonstration of interdigitating cell processes with desmosomes. Both tumors also showed unexpected immunoreactivity with muscle-specific actin. Follicular dendritic cell tumor merits wider recognition of its possible extranodal occurrence as well as its full morphological spectrum in order to better define its behavior.

Rehydration of air-dried smears with normal saline. Application in fluid cytology

Ninety fluid specimens (30 each of urine, ascitic and pleural fluid) were studied by preparing three comparable smears. One was air dried for Giemsa stain, one wet fixed in 95% ethanol and one dried on a hot plate at 37 degrees C, rehydrated in normal saline for 30 seconds and fixed in ethanol. The latter two were stained with Papanicolaou stain, and a comparison was made of the (1) retention of red blood cells, (2) retention of epithelial or mesothelial cells, and (3) cytologic preservation. The Giemsa-stained smear was used as a control for (1) and (2). Complete lysis of red blood cells was noted in the rehydration smears as compared with 70% red blood cell retention in the wet-fixed smears (P < .01). The rehydration smears retained 78% urothelial cells as compared with 55% in the wet-fixed smears (P < .01). For ascitic and pleural fluid the cell retention did not differ significantly. The wet-fixed smears scored better for overall cytologic preservation, but the difference was not significant. The rehydration smears showed a decrease in the chromaticity of staining, more flattened cell clusters and slight cell enlargement. The rehydration method was beneficial for urine and blood-stained body cavity fluids.