Specific inhibition of serine- and arginine-rich splicing factors phosphorylation, spliceosome assembly, and splicing by the antitumor drug NB-506.

Specific phosphorylation of serine- and arginine-rich pre-mRNA splicing factors (SR proteins) is one of the key determinants regulating splicing events. Several kinases involved in SR protein phosphorylation have been identified and characterized, among which human DNA topoisomerase I is known to have DNA-relaxing activity. In this study, we have investigated the mechanism of splicing inhibition by a glycosylated indolocarbazole derivative (NB-506), a potent inhibitor of both kinase and relaxing activities of topoisomerase I. NB-506 completely inhibits the capacity of topoisomerase I to phosphorylate, in vitro, the human splicing factor 2/alternative splicing factor (SF2/ASF). This inhibition is specific, because NB-506 does not demonstrate activity against other kinases known to phosphorylate SF2/ASF such as SR protein kinase 1 and cdc2 kinase. Importantly, HeLa nuclear extracts competent in splicing but not splicing-deficient cytoplasmic S100 extracts treated with the drug fail to phosphorylate SF2/ASF and to support splicing of pre-mRNA substrates containing SF2/ASF-target sequences. Native gel analysis of splicing complexes revealed that the drug affects the formation of the spliceosome, a dynamic ribonucleoprotein structure where splicing takes place. In the presence of the drug, neither pre-spliceosome nor spliceosome is formed, demonstrating that splicing inhibition occurs at early steps of spliceosome assembly. Splicing inhibition can be relieved by adding phosphorylated SF2/ASF, showing that extracts treated with NB-506 lack a phosphorylating activity required for splicing. Moreover, NB-506 has a cytotoxic effect on murine P388 leukemia cells but not on P388CPT5 camptothecin-resistant cells that carry two point mutations in conserved regions of topoisomerase I gene (Gly361Val and Asp709Tyr). After drug treatment, P388 cells accumulated hypophosphorylated forms of SR proteins and polyadenylated RNA in the nucleus. In contrast, neither SR protein phosphorylation nor polyadenylated mRNA distribution was affected in P388 CPT5-treated cells. Consistently, NB506 treatment altered the mRNA levels and/or splicing pattern of several tested genes (Bcl-X, CD 44, SC35, and Sty) in P388 cells but not in P388 CPT5 cells. The study shows for the first time that indolocarbazole drugs targeting topoisomerase I can affect gene expression by modulating pre-mRNA splicing through inhibition of SR proteins phosphorylation.

Marginal zone B-cell lymphoma of the salivary gland arising in chronic sclerosing sialadenitis (Küttner tumor).

We report a case of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type of the salivary gland arising in a background of chronic sclerosing sialadenitis. Chronic sclerosing sialadenitis is a common fibrosing chronic inflammatory lesion of the submandibular gland, which is thought to be the result of sialolithiasis, and is not associated with a systemic autoimmune disease. Salivary MALT lymphomas are typically associated with lymphoepithelial sialadenitis (LESA) in a patient with or without Sjögren's syndrome. Our case of salivary MALT lymphoma was neither preceded by Sjögren's syndrome nor accompanied by LESA. This case suggests that chronic inflammatory processes other than Sjögren's syndrome may provide a substrate for the development of MALT lymphoma.

Endocrine mucin-producing sweat gland carcinoma: a cutaneous neoplasm analogous to solid papillary carcinoma of breast.

We describe two cases of a distinctive in situ and invasive cutaneous adnexal neoplasm occurring in the eyelid. Mucinous carcinoma represented the invasive portion of the tumor in one case, whereas the other infiltrated in small solid nests. The in situ component is identical to the recently described solid papillary carcinoma of the breast (endocrine ductal carcinoma in situ). Both tumors produced intra- and extracellular mucin, exhibited endocrine differentiation by immunohistochemistry and ultrastructural analysis, and were positive for estrogen and progesterone receptors.

Lipofuscin pigmentation (so-called "melanosis") of the prostate.

Although intraepithelial pigment in the prostate gland has been termed melanosis, the nature of the pigment is not entirely clear, and many pathologists are not aware of its existence. We examined 863 hematoxylin and eosin (H + E) stained slides from 150 surgical specimens of prostate (69 needle biopsies, 66 transurethral resections, 14 radical prostatectomies, and 1 suprapubic prostatectomy) from 149 patients (age range, 47 to 90 years; mean 70 years) in an effort to characterize this pigment. The 1-3 microns in diameter, predominantly subnuclear, yellow-brown to gray-brown granules with a dark blue rim (by H + E) stained positively with Fontana-Masson, periodic acid-Schiff with diastase, Congo red, luxol fast blue, and oil-red-O and exhibited yellow autofluorescence consistent with lipofuscin. H + E stained slides revealed pigment in the benign epithelium in 86 of 150 cases (57%), within stromal macrophages in eight cases, and in atypical epithelium in two cases of high-grade prostatic intraepithelial neoplasia. Ten cases of invasive adenocarcinoma without recognizable pigment in H + E stained sections were stained by the Fontana-Masson technique, and pigment was identified in malignant epithelium in three of these cases. Ultrastructural examination of intraepithelial pigment in KII-fixed tissue from three radical prostatectomy specimens demonstrated the typical appearance of lipofuscin. Although intraepithelial pigment in prostatic biopsy or resection specimens is usually considered characteristic of seminal vesicle epithelium, our study demonstrates that lipofuscin is commonly present in epithelial cells of benign prostatic hyperplasia and less frequently in those of prostatic intraepithelial neoplasia and adenocarcinoma. The recognition of this pigment is important in preventing diagnostic confusion with seminal vesicle epithelium and with melanocytic lesions.

Solitary fibrous tumor of the nasal cavity and paranasal sinuses.

We report two solitary fibrous tumors of the nasal cavity and paranasal sinuses that were histologically and immunohistochemically virtually identical to solitary fibrous tumors (fibrous mesotheliomas) of the pleura. One tumor arose in a 48-year-old woman and the other in a 45-year-old woman. Both patients presented with nasal symptoms, and both patients are alive without evidence of disease 6 months and 1 year after excision. The tumors had a disorganized or "patternless" arrangement of spindle cells in a collagenous background and prominent vascular channels of varying size. Immunoperoxidase stains on paraffin sections showed staining of the cells for vimentin only; there was no staining for keratin, S-100 protein, desmin, and actin. Both cases presented some degree of diagnostic difficulty and had to be distinguished from other spindle cell tumors of the nasal cavity and paranasal sinuses, such as hemangiopericytoma, angiofibroma, and fibrous histiocytoma.

Solitary fibrous tumor of the orbit.

We report three cases of an orbital soft tissue lesion that fulfills the histologic, immunohistochemical, and electron microscopic criteria for solitary fibrous tumor, an entity previously described as a pleural tumor, but recently reported to occur in other locations. All three patients presented with proptosis. Two of the patients were cured by simple excision, and one patient had two recurrences, the last recurrence incompletely excised. The findings indicate that solitary fibrous tumor can occur in the orbit and, like solitary fibrous tumors of other anatomic sites, may behave in a nonaggressive or occasionally, locally aggressive fashion, with as yet no metastatic potential demonstrated in orbital lesions.

Immunohistologic diagnosis of orbital lymphoid infiltrates.

The distinction between benign and malignant lymphoid infiltrates of the orbit may be impossible on routine histopathologic sections. However, the detection of monotypic immunoglobulin is useful in distinguishing neoplastic from benign infiltrates. Since diagnostic frozen sections are often performed on biopsies of orbital masses to determine the adequacy of the biopsy and to provide a preliminary diagnosis, we stained additional frozen sections of 20 predominantly lymphoid infiltrates by an immunoperoxidase technique with antisera to immunoglobulin heavy and light chains. On routine sections, nine cases were malignant lymphoma, three were follicular hyperplasia, and eight (42%) were dense lymphocytic infiltrates of indeterminate nature. The nine lymphomas had monotypic immunoglobulin staining. The three histologically benign lesions had polytypic immunoglobulin. Six of the eight indeterminate lesions had monotypic immunoglobulin, supporting a diagnosis of lymphoma; two had polytypic staining. There was evidence of disseminated lymphoma at the time of diagnosis in five of nine patients with histologically malignant lesions and three of five with monoclonal indeterminate lesions for whom the information was available. Staining with monoclonal antibodies to T-cells revealed variable numbers of T-cells in all cases; their number and distribution did not distinguish benign from malignant lesions. The immunoperoxidase technique on frozen sections permits optimal use of small biopsy specimens for both morphologic and immunologic diagnosis. The majority of histologically indeterminate orbital lymphoid infiltrates were shown to be monoclonal.

Sinonasal lymphoma: a clinicopathologic analysis of 58 cases from the Massachusetts General Hospital.

Few large series compare lymphomas of the nasal cavity with those of the paranasal sinuses. We studied the cases of 58 patients, 34 males and 24 females, aged 7 to 92 years (mean, 57 years), who had lymphoma involving the nasal cavity or paranasal sinuses. Thirty-three patients had diffuse large B-cell lymphoma (DLBCL). Twenty-three were male and 10 were female, with an age range of 7 to 91 years (mean, 63 years); two were HIV-positive. Only 2 of 11 cases tested (one in an HIV-positive patient and one of lymphomatoid granulomatosis type) were Epstein-Barr virus (EBV)-positive. Thirty (91%) involved paranasal sinuses, 10 with nasal involvement, whereas three cases had nasal, but not sinus, involvement. At last follow-up, 16 (67%) were free of disease 7 to 169 months later (mean, 65 months), and 8 (33%) had died of disease 2 to 166 months later (mean, 45 months). Seventeen patients had nasal-type natural killer (NK)/T-cell lymphoma. There were 10 women and 7 men, aged 27 to 78 years (mean, 48 years). Thirteen of 14 were EBV-positive. Sixteen patients had nasal involvement, eight with sinus involvement. Eleven (73%) of 15 were alive and well 6 to 321 months later (mean, 139 months), three (20%) died of lymphoma 1, 11, and 12 months later, and one (7%) is alive with disease. There was one case each of marginal zone B-cell lymphoma, Burkitt's lymphoma, Burkitt-like lymphoma, peripheral T-cell lymphoma of unspecified type, and adult T-cell lymphoma/leukemia. In an additional three cases, the lymphomas were composed predominantly of large cells, but no immunophenotyping could be performed for subclassification. In 19 cases (17 DLBCLs, 1 Burkitt-like lymphoma, and 1 lymphoma of uncertain lineage), presenting symptoms included complaints related to the eyes. In 16 cases (13 DLBCLs, 1 Burkitt-like lymphoma, 1 nasal NK/T-cell lymphoma, and 1 lymphoma of uncertain lineage), the orbit was invaded by lymphoma. In our series, the most common lymphoma to arise in the sinonasal area is DLBCL, followed by nasal NK/T-cell lymphoma. Comparison of these two types of lymphoma showed that lymphomas involving sinuses without nasal involvement were predominantly DLBCLs (20 of 21), whereas nasal cavity lymphomas without sinus involvement were usually NK/T-cell type (8 of 11) (p = 0.000125). Compared with patients with DLBCL, patients with nasal NK/T-cell lymphoma were overall younger, with a lower male-to-female ratio. Lymphomas of B-cell lineage were more likely to be associated with symptoms related to the eyes (p < 0.0005) and to have extension to the orbit (p < 0.01) than were lymphomas of T- or NK-cell lineage. In contrast to results of Asian studies in which nasal NK/T-cell lymphoma has a very poor prognosis, our nasal NK/T-cell lymphomas had an outcome similar to that of DLBCL.

Carcinoid tumor of the middle ear.

A primary tumor of the middle ear with histologic, histochemical, and ultrastructural features of a neuroendocrine neoplasm is described. This neoplasm superficially resembles the so-called adenomatous tumor of the middle ear, and potential relationships and differences between these tumors are discussed. Although the histogenesis of the carcinoid tumor of the middle ear is not well understood, it most likely originates from pre-existing neuroendocrine cells or a primitive precursor cell. This neoplasm should be considered in the differential diagnosis when biologically low-grade tumors with prominent acinar or trabecular architectures are encountered in the middle ear. Since the carcinoid tumor of the middle ear is presumably of foregut derivation, stains for argyrophilic granules and electron-microscopic identification of neurosecretory granules are important diagnostic aids.

CD44 expression in sinonasal inverted papillomas and associated squamous cell carcinoma.

Increased expression of the cell adhesion molecule, CD44 standard form (CD44s), has been associated with papillary epithelial tumors, and decreased expression has been linked to tumor invasion and metastasis. Sinonasal inverted papillomas (SIPs) are the most common papillary tumors of the sinonasal tract. This study tests whether the development of squamous cell carcinoma (SCC) in situ and invasive SCC in SIP is associated with altered expression of CD44s. Seventy-six specimens of SIP from 68 patients, 2 specimens of SIP with focal SCC in situ, and 10 specimens of invasive SCC arising in SIP were studied. Automated immunohistochemistry was performed for CD44s expression on paraffin-embedded tissue sections using mouse antihuman CD44 antibody. All 76 SIPs (100%) expressed CD44 (strong membranous staining, 83%; moderate staining, 12%; weak staining, 5%). Two (100%) of 2 SIPs with SCC in situ maintained strong expression in benign and severely dysplastic foci. Six (60%) of 10 SIPs with SCC showed complete loss of CD44s expression, while 4 (40%) of 10 cases of SIP with SCC showed weak expression. Two SIPs with SCC (20%) featured weak diffuse staining of the SCC component, and 2 SIPs with SCC (20%) featured weak focal staining of the SCC component. The non-SCC SIP components of the 10 SIPs with SCC uniformly featured intact membranous CD44 staining. As in other papillary epithelial neoplasms, the typical benign SIP features diffuse membranous CD44s expression. In cases of SIP developing an invasive SCC, CD44s expression in the SCC component is frequently lost.

A novel, noninvasive imaging technique for intraoperative assessment of parathyroid glands: confocal reflectance microscopy.

BACKGROUND: Successful surgical management of primary hyperparathyroidism requires the ability to identify and distinguish normal from abnormal parathyroid tissue. Microscopic pathologic confirmation often helps with the diagnoses and decisions regarding the extent of parathyroid resection. Confocal reflectance microscopy (CRM) is an optical method of noninvasively imaging tissue without fixation, sectioning, and staining as in standard histopathology. The goal of this study was to determine if CRM imaging could be used to distinguish normal from diseased parathyroid tissue intraoperatively. METHODS: In this study, 44 parathyroid glands from 21 patients undergoing operations for primary hyperparathyroidism were imaged immediately after excision. CRM images were compared with conventional hematoxylin-and-eosin stained sections obtained from the same gland. The percentage area occupied by fat cells was calculated in images of both normal and diseased glands. RESULTS: Characteristic microscopic features of parathyroid glands were distinguishable by CRM and correlated well with histopathology. The stromal fat content of normal and diseased glands could easily be determined. The percentage area occupied by fat cells differed significantly (P <.00001) in normal glands (average, 23.0% +/- 10.9%) and adenomatous glands (average, 0.4% +/- 0.7%). CONCLUSIONS: CRM imaging rapidly revealed microscopic features that reliably differentiated normal and diseased parathyroid glands. The success of this preliminary ex vivo study promotes interest in further development of an in situ probe for in vivo clinical diagnostic use.

Meningiomas presenting in the paranasal sinuses and temporal bone.

Head and neck meningiomas are primarily intracranial neoplasms; they rarely present in extracranial locations. Two cases of meningiomas in the paranasal sinuses and seven cases in the temporal bone are described. The pathology, pathogenesis, clinical evaluation, and therapy are discussed. It is stressed that intracranial components of such meningiomas be sought and, as appropriate, treated.

Heterotopic cervical salivary gland tissue in a family with probable branchio-otorenal syndrome.

Heterotopic cervical salivary gland tissue was found in a 4-yr-old girl with branchial and otologic abnormalities. Her mother and sister also had heterotopic cervical salivary tissue in association with anomalies that suggest the branchio-otorenal (BOR) syndrome. Heterotopic cervical salivary gland tissue may result from abnormal branchial development.

Polycystic disease of the parotid glands.

A 31-year-old woman had bilateral swelling of the parotid glands at 4 months of pregnancy. MR imaging showed marked enlargement of the parotid glands with increased signal on images with long repetition times. A diagnosis of polycystic disease of the parotid gland was made after biopsy and histologic examination. The radiographic and histologic features of this rare disease are discussed.

Necrotizing sialometaplasia in the setting of acute and chronic sinusitis.

Necrotizing sialometaplasia is a benign lesion that may be mistaken for mucoepidermoid or squamous cell carcinoma. A case report is presented in which necrotizing sialometaplasia was noted as an incidental finding in the setting of acute and chronic sinusitis. It is critical to recognize the lesion as benign so as to avoid overdiagnosis and overtreatment.

Differential expression of transthyretin in papillary tumors of the endolymphatic sac and choroid plexus.

Aggressive papillary tumors of the temporal bone, occurring sporadically or as part of von Hippel-Lindau disease, have been shown to originate within the endolymphatic sac or duct. Also implicated as a potential precursor from which some of these tumors may arise is ectopic choroid plexus epithelium. To aid in the differentiation between papillary tumors of endolymphatic sac and duct origin and those arising from choroid plexus, an immunohistochemical study using stains for transthyretin (TTR), cytokeratins, S-100 protein, epithelial membrane antigen (EMA), and glial fibrillary acidic protein (GFAP) was carried out on archival specimens of normal and neoplastic endolymphatic sac and duct and choroid plexus epithelium. Transthyretin, a marker for choroid plexus epithelium, was found to show differential expression between choroid plexus papillomas and aggressive papillary tumors of the endolymphatic sac or duct. Therefore the use of TTR in concert with other immunohistochemical stains appear to aid in the differentiation between intracranial and intratemporal papillary tumors arising from choroid plexus and endolymphatic sac or duct epithelium.

Laryngeal tuberculosis as manifested in the decades 1963-1983.

Laryngeal tuberculosis is usually a complication of pulmonary tuberculosis and the clinical patterns have changed in recent decades. To evaluate the changing patterns, we reviewed 15 patients seen at the Massachusetts Eye and Ear Infirmary over a 20-year period and diagnosed as having laryngeal tuberculosis. The results showed a mean age of 56 years; a male predominance by a 2:1 ratio; minimal pulmonary lesions on radiographic studies in nine patients and one normal radiograph; clinical simulation by the tuberculous lesion of laryngeal cancer; excellent response to antituberculosis therapy; and low infectivity. Laryngeal lesions and concurrent pulmonary lesions should alert the otolaryngologist to consider systemic disease processes and the most frequent granulomatous lesion of the larynx, tuberculosis.

Endolymphatic sac tumors: histopathologic confirmation, clinical characterization, and implication in von Hippel-Lindau disease.

The term "endolymphatic sac tumor" (ELST) was coined to identify the likely origin of aggressive papillary tumors of the temporal bone. To evaluate the validity of this designation, the temporal bone collection at the Massachusetts Eye and Ear Infirmary was accessed in an effort to determine the pathologic relationship between these tumors and the endolymphatic sac. The search resulted in the identification of a de-novo papillary epithelial lesion arising within the confines of the endolymphatic sac in a patient with von Hippel-Lindau (VHL) disease who harbored a large, destructive ELST in the opposite temporal bone. This finding provides the most substantial evidence to date regarding the origin of the ELST and the accuracy of its nomenclature. Seven additional clinical cases of ELST were identified and analyzed in order to define the natural history of these tumors. All patients had a history of sensorineural hearing loss diagnosed an average of 10.6 years prior to tumor discovery. The presence of a polypoid external auditory canal mass, facial paralysis, and evidence of a destructive mass arising on the posterior fossa surface of the temporal bone were common physical and radiographic findings. The management of these patients, as well as those who are probably prone to such tumors (i.e., VHL patients), is discussed.

Anti-EBV serologic tests for nasopharyngeal carcinoma.

Sixty-three serum specimens from American patients with nasopharyngeal carcinoma were examined for antibodies to antigens associated with Epstein-Barr virus (EBV) and compared with 98 specimens from patients with other head and neck cancers, 133 from patients with benign head and neck diseases, and 96 from healthy donors. The level of antibody titers to EBV-associated antigens was correlated with nasopharyngeal carcinoma. The anti-EBV profile of elevated antibody titers directed against viral capsid antigen and early antigen was seen in undifferentiated and nonkeratinizing tumors but usually not in squamous cell tumors. Titers tended to rise with large increases in total tumor burden caused by distant metastases, often before clinical evidence of metastases. At the time of diagnosis, antibody-dependent cellular cytotoxicity testing was performed on serum samples from 46 of the patients with nasopharyngeal carcinoma. Pretreatment titers were usually low in patients in whom recurrence developed and were high in most of the patients who had a good response to treatment and have remained free of recurrence.

A comparison of paraganglioma, carcinoid tumor, and small-cell carcinoma of the larynx.

Laryngeal paraganglioma, carcinoid tumor, and small-cell carcinoma are rare. Histologically they are similar to analogous tumors in other locations but may be difficult to identify in small biopsy specimens. We compared the light microscopic, histochemical, immunohistochemical, and electron microscopic features of two laryngeal paragangliomas, one carcinoid tumor, and six small-cell carcinomas. The paraganglioma chief cells stained with Grimelius stain and for chromogranin and neuron-specific enolase. The carcinoid tumor cells stained with Grimelius stain and for chromogranin, serotonin, neuron-specific enolase, and keratin. The small-cell carcinoma cells stained for keratin and neuron-specific enolase. The patients with paragangliomas and carcinoid tumor remain healthy through 20 months of follow-up. Four of the patients with small-cell carcinomas have died. Distinction between these tumors is warranted by differing histologic appearances, staining characteristics, and biologic behavior.