A benign neoplasm with histopathological features of both schwannoma and retiform perineurioma (benign schwannoma-perineurioma): a report of six cases of a distinctive soft tissue tumor with a predilection for the fingers

We present six cases of a distinctive soft tissue tumor which occurred in five women and one man. None of the patients had signs of neurofibromatosis. All tumors occurred on the fingers ( n=5) or the thenar eminence of the hand ( n=1). The mean age of the patients was 33 years. The tumors were 1-2.5 cm in diameter (mean size 1.6 cm). Three patients with follow-up were without signs of recurrence or metastasis. Microscopically the lesions were nonencapsulated and featured a multilobular architecture and both myxoid and pseudocystic change. The lobules varied in size and shape and were separated by variably thickened, dense, sclerotic/collagenous septae. The lobules were composed of two components: schwannomatous and perineuriomatous. The schwannomatous component was immunohistochemically S-100 protein positive and CD34 and EMA negative, and the perineuriomatous component had the appearance of retiform perineurioma. The perineurial parts were mostly S-100 protein and CD34 negative and EMA positive. These two components either formed separate nodules or the schwannomatous tissue surrounded the perineurial parts located in the centers of the lobules. We interpreted the lesions as hybrid tumors with features of schwannoma and retiform perineurioma.

Cylindroma of the Breast of Skin Adnexal Type

Four cases of solitary cylindroma of the breast of skin adnexal type are described. The tumors were morphologically and immunophenotypically identical to their dermal counterparts. They arose in close proximity to the nipple, such as the retroareolar area of the breast and in intimate association with the lactiferous ducts, suggesting an origin from the latter structures. One case occurred in a woman with hereditary multiple cylindromatosis (Brooke-Spiegler syndrome). This is the second reported case of this hereditary syndrome with extracutaneous manifestations and the first case in which the breast is involved.

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature

Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting. The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO. Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors. Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO. The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied. Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed. The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years). A long history of OO was common. The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9). The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 1.7 to 14 cm. Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification. Four of these benign-appearing PMTMCTs contained osteoid-like matrix. Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant. The 3 cases without known OO were histologically identical to the typical PMTMCT. Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma. Three cases expressed actin; all other markers were negative. Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR. Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases). We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT. Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors. Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO.

Evaluation of a DHPLC-based assay for rapid detection of RET germline mutations in Italian patients with medullary thyroid carcinoma

Causative gain-of-function mutations of the RET tyrosine-kinase receptor gene have been reported in more than 95% of inherited cases of medullary thyroid carcinoma (MTC; OMIM# 155240). Most RET activating mutations are clustered in mutational "hot spots" in exons 10, 11, 13, 14, 15 and 16 and are usually detected by single-strand conformation polymorphism (SSCP) followed by direct sequencing. To improve sensitivity, time and costs of mutational screening we have developed a denaturing high performance chromatography (DHPLC) protocol, based on the detection of heteroduplex molecules by ion-pair reverse-phase liquid chromatography under partially denaturing conditions. The mutational screening of RET exons 10, 11, 13-16 was performed in a total of 111 subjects, including 45 MTC patients and 49 relatives with known RET mutations and 17 individuals, being at risk of hereditary MTC and carrying unknown RET alleles. Heteroduplex peaks with a distinct and reproducible DHPLC elution profile allowed the detection of both rare and common RET mutations. Overall, the DHPLC-based methodology showed a high level of sensitivity and accuracy, nearing 100%. Furthermore, our protocol showed the ability to identify: 1) all the mutated codons of RET located in the "hot spots" domain; 2) the different point mutations occurring in the same codon of RET gene; 3) less frequent or rare mutations; 4) polymorphisms. As such, it can be proposed as a relatively simple and highly accurate method for a rapid genetic testing for members of MTC families.

Proteomic and postproteomic characterization of keratan sulfate-glycanated isoforms of thyroglobulin and transferrin uniquely elaborated by papillary thyroid carcinomas

Previous studies have suggested that surface components of papillary thyroid carcinoma (PTC) cells may be aberrantly glycanated, but the precise nature of these molecules has not been unveiled nor documented to be of clinical relevance. A monoclonal antibody was raised against a unique keratan sulfate (KS) determinant and used to differentially screen benign and malignant thyroid tissue for the expression of components carrying these moieties. In a total of 349 cases of benign and malignant thyroid lesions, 100% of the 115 PTC cases examined (including various histological subtypes) were found to contain KS-bearing molecules, whereas these were virtually absent from benign tissues and other thyroid tumors, with the exception of 21% of the follicular carcinoma cases analyzed. A composite immunoaffinity chromatography, immunochemistry, and mass spectrometric approach revealed that the PTC-specific KS-bearing macromolecules were unique glycoforms of thyroglobulin and transferrin. Combined, reciprocal immunoprecipitation and Western blotting further indicated that the former glycoform predominated and that most of the transferrin produced by PTC was glycanated with KS moieties. Fluorescent keratanase II-based fingerprinting of the KS moieties bound to these isoforms further demonstrated several PTC-specific peculiarities: 1) that a considerable portion of the moieties was covalently attached via a novel core protein linkage structure; 2) they had an unusual extended average length; 3) an unusual relative ratio of highly sulfated disaccharides terminating with alpha (2-3)-linked N-acetylneuraminic acid capping residues; and 4) a novel unidentified oligosaccharide moiety at the nonreducing terminus. Comparative analysis of the relative distribution of transferrin in benign versus PTC tissues highlighted a marked malignancy-associated abundance of the molecule, with a >75% frequency in expression in PTC. These findings demonstrate that PTC cells synthesize unique post-translationally modified thyroglobulin and transferrin variants in situ that may be directly exploitable for diagnosis, through histological and noninvasive cytological procedures; for devising novel strategies for antibody-guided imaging of this tumor in vivo; and for postsurgery follow-up of PTC patients.

Frequency of microsatellite instability in unselected sebaceous gland neoplasias and hyperplasias

Sebaceous gland neoplasias are the cutaneous manifestation of the Muir-Torre syndrome, which is known to be a phenotypical variant of hereditary nonpolyposis colorectal cancer. Both hereditary nonpolyposis colorectal cancer and Muir-Torre syndrome are caused by inherited DNA mismatch repair defects. As a prominent molecular genetic feature, all tumors associated with a DNA mismatch repair defect exhibit high microsatellite instability. So far, the frequency of DNA mismatch repair defects in patients selected solely on the basis of a sebaceous gland tumor has never been determined. In order to estimate this frequency, we assessed microsatellite instability with up to 10 microsatellite markers in a newly collected unselected series of 25 sebaceous gland neoplasias (six sebaceous adenomas, 16 sebaceous epitheliomas, three sebaceous carcinomas) in comparison to 32 sebaceous gland hyperplasias from unrelated patients. As many as 15 of the 25 sebaceous gland neoplasias (60%), but only one of the 32 sebaceous gland hyperplasias (3%), exhibited high microsatellite instability. Thus, in our study, the majority of patients with a sebaceous gland neoplasia in contrast to patients with a sebaceous gland hyperplasia are highly suspicious for an inherited DNA mismatch repair defect. On the basis of the subsequently collected tumor histories, nine of the 15 patients with a high microsatellite unstable sebaceous gland neoplasia were identified to have Muir-Torre syndrome. In none of these cases, however, were the clinical Amsterdam criteria for diagnosing hereditary nonpolyposis colorectal cancer fulfilled. In the sebaceous tumors of the remaining six patients, high microsatellite instability was an incidental finding. In two of these six patients, single relatives were known to be affected with internal cancer; however, their family histories were not suggestive of Muir-Torre syndrome or hereditary nonpolyposis colorectal cancer. In comparison with microsatellite instability screening studies in a variety of other randomly selected tumors, our study identifies sebaceous gland neoplasias as tumors with the highest frequency of high microsatellite instability reported so far, whereas sebaceous gland hyperplasia rarely exhibits high microsatellite instability. Therefore, screening for microsatellite instability in sebaceous gland neoplasias will be of great value in the detection of an inherited DNA mismatch repair defect, which predisposes to various types of internal cancers.

H-caldesmon expression in myofibroblastoma of the breast: evidence supporting the distinction from leiomyoma

AIMS

The ultrastructural detection of leiomyomatous rather than myofibroblastic features in some cases of myofibroblastoma of the breast led some electron microscopically orientated pathologists to doubt the commonly accepted myofibroblastic nature of such a tumour, so the alternative terms 'myogenic stromal tumour' or 'variant of leiomyoma' have been proposed. The aim of this study was to analyse the immunohistochemical expression of h-caldesmon, a reliable marker in distinguishing smooth muscle versus myofibroblastic cellular differentiation, in a large series of myofibroblastomas of the breast to clarify whether these tumours are basically leiomyomatous. Moreover, cases from primary myofibroblastic lesions of the breast, such as fibromatosis and inflammatory myofibroblastic tumour, were analysed to assess whether h-caldesmon expression parallels that observed in their soft tissue counterparts.

METHODS AND RESULTS

Paraffin-embedded sections from 12 cases of myofibroblastoma, seven cases of fibromatosis, and one case of inflammatory myofibroblastic tumour were evaluated immunocytochemically for the expression of h-caldesmon. As expected, all myofibroblastic lesions failed to express h-caldesmon. Conversely, focal staining, ranging from 2% to 10% of neoplastic cells, was detected in myofibroblastomas, even though it was restricted to 50% of analysed cases.

CONCLUSIONS

Our results, indicating that smooth muscle differentiation occurs in a minority of the myofibroblastoma cells exclusively in half of the analysed cases, support the separation of myofibroblastoma from leiomyoma. The detection of smooth muscle cells in breast myofibroblastoma is easily explained if we postulate its histogenesis from the CD34+ fibroblasts of mammary stroma capable of multidirectional mesenchymal differentiation, including smooth muscle. We recommend retention of the term myofibroblastoma for all the desmin-positive and/or alpha-smooth muscle actin-positive spindle cell tumours of the breast consistent with the previously well-established morphological criteria for such neoplasms, unless one is dealing with a typical leiomyoma easily recognizable at light microscopy.

Serum thyroglobulin and 131I whole body scan after recombinant human TSH stimulation in the follow-up of low-risk patients with differentiated thyroid cancer

OBJECTIVE

The 'standard' postoperative follow-up of patients with differentiated thyroid cancer (DTC) has been based upon serum thyroglobulin (Tg) measurement and (131)I whole body scan ((131)I-WBS) after thyroid hormone (T(4)) treatment withdrawal. However, (131)I-WBS sensitivity has been reported to be low. Thyroid hormone withdrawal, often associated with hypothyroidism-related side effects, may now be replaced by recombinant human thyroid stimulating hormone (rhTSH). The aim of our study was to evaluate the diagnostic accuracy of (131)I-WBS and serum Tg measurement obtained after rhTSH stimulation and of neck ultrasonography in the first follow-up of DTC patients.

DESIGN

Ninety-nine consecutive patients previously treated with total thyroidectomy and (131)I ablation, with no uptake outside the thyroid bed on the post-ablative (131)I-WBS (low-risk patients) were enrolled.

METHODS

Measurement of serum Tg and (131)I-WBS after rhTSH stimulation, and ultrasound examination (US) of the neck.

RESULTS

rhTSH-stimulated Tg was <or=1 ng/ml in 78 patients (Tg-) and >1 ng/ml (Tg+) in 21 patients, including 6 patients with Tg levels >5 ng/ml. (131)I-WBS was negative for persistent or recurrent disease in all patients (i.e. sensitivity = 0%). US identified lymph-node metastases (confirmed at surgery) in 4/6 (67%) patients with stimulated Tg levels >5 ng/ml, in 2/15 (13%) with Tg >1<5 ng/ml, and in 2/78 (3%) who were Tg-negative.

CONCLUSIONS

(i) diagnostic (131)I-WBS performed after rhTSH stimulation is useless in the first follow-up of DTC patients; (ii) US may identify lymph node metastases even in patients with low or undetectable serum Tg levels.

[Fibromatosis of the breast: a clinical, radiological and pathological study of 6 cases]

We describe the clinical, radiological and pathological features of a series of six cases of primary fibromatosis of the breast. Most patients (5 of 6) were women of 22-58 years of age; one case occurred in a 47-year-old man. The fibromatosis of the breast in all cases presented as a monolateral solid nodule, clinically suspicious for malignancy and in three cases was also associated with cutaneous and/or nipple retraction. None of the patients was affected by any genetic disorder characterized by fibromatoses involving multiple sites, including breast. Both echographic and mammographic examinations revealed solid masses with irregular margins but without calcifications, mimicking scirrhous carcinoma. All cases were surgically treated by lumpectomy (4 of 6) or quadrantectomy (2 of 6), and after a follow-up period ranging from 5 months to 13 years all patients are well and disease-free. Histological examination revealed finger-like infiltrating margins entrapping adjacent breast parenchyma and adipose tissue in all cases. The hallmark of the lesion was the presence of bland-looking spindle cells, with a low mitotic index, organized in long sweeping and intersecting fascicles. Three different morphological phases (i.e. proliferative, involutional and residual), identical to those observed in Dupuytren's superficial fibromatosis, variably coexisted in each case. At immunohistochemistry the cells which comprised the lesion exhibited a diffuse expression of vimentin and a heterogeneous immunoreactivity to a-smooth muscle actin, thus confirming their fibro-myofibroblastic nature. No expression of estrogen, progesterone or androgen receptors or of pS2 correlated-estrogen protein was observed. We discuss both the pathogenesis of the mammary fibromatosis, pointing to the fibroblastic cells of the mammary stroma as the putative precursors, and the differential diagnosis versus the bland-looking, monomorphic spindle cell tumor-like or tumorous lesions of the breast.

Diagnosis of hepatocellular carcinoma complicating liver cirrhosis: utility of repeat ultrasound-guided biopsy after unsuccessful first sampling

PURPOSE

To evaluate the utility of a second ultrasound-guided fine-needle biopsy of liver nodules thought to be hepatocellular carcinoma when the original biopsy has failed to provide a reliable diagnosis.

METHODS

Thirty-seven cirrhotic patients underwent ultrasound-guided fine-needle biopsy of liver nodules that were subsequently diagnosed as hepatocellular carcinoma. Each biopsy involved a single puncture with a 20 G cutting needle, which yielded pathologic material used both for cytologic and histologic studies. In 23 cases (mean diameter of nodules 48 mm) the biopsy furnished exclusively necrotic material (non-diagnostic subgroup); in the other 14 cases (mean diameter 26 mm) the biopsy yielded no neoplastic elements (false-negative subgroup). All 37 nodules were subjected to repeat biopsies performed in the same manner.

RESULTS

The repeat biopsies provided a diagnosis of hepatocellular carcinoma in six of the 23 patients from the non-diagnostic subgroup and in seven of the 14 in the false-negative subgroup. Overall, repeat biopsy produced a diagnostic gain of 35.1%.

CONCLUSION

The chance of success with repeat biopsy of hepatocellular carcinoma is limited and may depend to some extent on the characteristics of the lesions (i.e., areas of necrosis in large nodules, well-differentiated cellular populations in small ones).

Gigantic cutaneous horns of the scalp: lesions with a gross similarity to the horns of animals: a report of four cases

Gigantic cutaneous horns, grossly similar to the horns seen in animals, are exceedingly rare in humans. After finding one case in practice, we searched our departmental files for similar cases and examined them grossly and microscopically. Four cases were identified. All occurred as solitary lesions in older women on the parietal-occipital region of the scalp. They had a growth history of up to 30 years; the women hid these horns in their hair. Grossly, the horns were yellow-grey, and there were shallow furrows running along the length of the horns. The length ranged from 17 to 25 cm, and the width was up to 2.5 cm. All four lesions showed similar histologic changes. Microscopically, the gigantic horns consisted of a mixture of squamous epithelial cells and tricholemmal keratinized debris. In one case the base of the horn was directly connected with a mass composed of benign tricholemmal cysts of the scalp. Mitoses were common, but atypical mitoses were not observed. The nuclei of the squamous cells were bland without pleomorphism, hyperchromasia, or atypia. Follow-up of all patients was uneventful: all patients were well and without signs of recurrence or metastasis 2-15 years after the surgical excision. Gigantic cutaneous horns are rare and benign. We think that they represent an extremely well-differentiated variant of proliferating tricholemmal tumor with an unusual and remarkable gross pattern.

Aphasia as a rare presentation of monosymptomatic demyelinating disease: case report and review of the literature

We present a case of sudden-onset aphasia due to a single pathological lesion, which at neuroradiological imaging studies was suggestive of glioma, while on biopsy proved be of demyelinating nature. Every cause of demyelinating lesions of the central nervous system was considered in the differential diagnosis, concluding for a primary demyelinating disease. The clinical and radiological differences between multiple sclerosis and acute disseminated encephalomyelitis are discussed. Although aphasia has already been described in demyelinating diseases, we underline its rarity as onset symptom.

Spindle cell lipoma-like tumor, solitary fibrous tumor and myofibroblastoma of the breast: a clinico-pathological analysis of 13 cases in favor of a unifying histogenetic concept

We reviewed the clinico-pathological features of a series of 13 cases of benign spindle stromal tumors (BSSTs) of the breast relating to a basic common theme consisting of a well-circumscribed proliferation of vimentin+/CD34+/BCL-2+/CD99+ spindly to oval-epithelioid cells, variably arranged in haphazard to short fascicular growth pattern, with interspersed thick or thin collagen bands. Morphological variations included atypical mono- or multi-nucleated cells in five cases and a mature lipomatous tumor component, varying from focal to prominent, in eight cases. Based on morphological and immunophenotypical features, a distinction was made between two main subtypes of these tumors--fibroblastic and myofibroblastic. The former subtype included two cases respectively represented by a typical solitary fibrous tumor (SFT) and a neoplasm labeled "spindle-cell lipoma (SCL)-like tumor", closely reminiscent of soft tissue SCL. Both tumors had cells with fibroblastic-like appearance, haphazardly arranged and immunoreactive for vimentin, CD34, BCL-2, and CD99. The latter subtype, comprised nine cases exhibiting evidence of myofibroblastic differentiation (desmin and alpha-smooth muscle actin) which were classified as myofibroblastomas (MFBs). The remaining two cases were defined as "mixed BSSTs", having typical features of diverse neoplasms, respectively represented by a case of MFB with focal SFT and pleomorphic/SCL-like areas, and SFT with focal MFB-like component. The common basic morpho-immunophenotypical features, the possibility that both fibroblastic and myofibroblastic tumors may contain an additional mature lipomatous component, and the existence of hybrid stages (mixed BSSTs) strongly support the view that such tumors belong to the same category of lesions. We postulate that the precursor of all these neoplasms is the vimentin+/CD34+ cells of the mammary stroma, the well-known inherent plasticity of which to differentiate toward several mesenchymal lines, provides the explanation for the phenotypic heterogeneity of these neoplasms. Accordingly, the encompassing term "benign spindle stromal tumors of the breast" is advocated for such tumors.

Diagnosis of liver nodules observed in chronic liver disease patients during ultrasound screening for early detection of hepatocellular carcinoma

OBJECTIVES

The aim of our study was to evaluate the nature of focal liver lesions detected during the ultrasound follow-up of a population (prevalently anti-hepatitis C virus [anti-HCV] positive) with chronic liver disease.

METHODS

The study population consisted of 1827 consecutive newly diagnosed chronic liver disease cases without liver nodules at enrollment. Patients were screened at 4-month intervals by ultrasound and serum alpha-fetoprotein assessment. All lesions detected on imaging studies (except those accompanied by diagnostic a-fetoprotein levels) were subjected to biopsy (histology and cytology).

RESULTS

During the 7-yr follow-up period (mean = 43.1 months), one or more solid focal lesions were found in 287 patients. a-Fetoprotein was diagnostic for hepatocellular carcinoma in 51 patients. Ultrasound-guided fine-needle biopsy was performed in the remaining 236 patients, yielding a diagnosis in 214: 198 hepatocellular carcinomas, 11 dysplastic nodules, and five B-cell non-Hodgkin's lymphomas (all confined to the liver and all in patients with chronic HCV infection). Twenty-two patients with nondiagnostic biopsies received diagnoses of hepatocellular carcinoma (20) or dysplastic nodules (two) based on arteriography or surgical biopsy.

CONCLUSIONS

Focal lesions arising in patients with HCV-related chronic liver disease can be other than hepatocellular carcinoma, and ultrasound-guided fine-needle biopsy plays an important role in their diagnosis. The prevalence of non-Hodgkin's lymphoma in this selected population was 0.31%. The fact that all five lymphoma patients had cirrhosis related to hepatitis C strengthens the hypothesis of an etiological correlation between the latter infection and B-cell lymphoproliferative disorders.

Benign spindle cell tumors of the mammary stroma: diagnostic criteria, classification, and histogenesis

Purely benign mesenchymal spindle cell neoplasms of the breast are currently labeled under various terms in the literature (benign spindle cell tumor, fibroma, spindle cell lipoma, myofibroblastoma, solitary fibrous tumor, myogenic stromal tumor). The lack of strict diagnostic criteria to clearly indicate such mesenchymal neoplasms is the main reason which generated the risk of terming the same lesion under different names or, conversely, of collecting different types under the same term. Although such neoplasms exhibit morphological and immunophenotypical heterogeneity, they actually represent variations of the same tumor entity, likely arising from the uncommitted vimentin+/CD34+ fibroblasts of the mammary stroma, capable of multidirectional mesenchymal differentiation. To cover the entire spectrum of such lesions, the term "benign spindle cell tumors (BSCTs) of the mammary stroma" is advocated. BSCTs can be subtyped into four main groups by light microscopy (LM) and immunocytochemistry (ICC): fibroblastic, myofibroblastic, fibrohistiocytic, and mixed forms. A simple and practical approach to a nosologically correct diagnosis and a list of differential diagnoses are presented. The awareness of the diversity of morphological and immunophenotypical features of BSCTs of the mammary stroma, including uncommon variants, is helpful to avoid confusion with other monomorphic bland-looking benign and malignant spindle cell tumors and tumor-like lesions of the breast.

HLA-DQA1 and -DQB1 genes and Helicobacter pylori infection in Italian patients with gastric adenocarcinoma

Both HLA-DQA1 and -DQB1 genes and Helicobacter pylori infection have been linked to gastric cancer. The aim of this work was to determine if HLA-DQA1 and -DQB1 alleles are presented at altered frequency in Italian patients with gastric adenocarcinoma and H. pylori infection. Oligotyping for HLA-DQA1 and -DQB1 and H. pylori serology was performed for 50 patients with gastric adenocarcinoma and compared with 80 patients with colonic adenocarcinoma and 179 healthy subjects. H. pylori infection was present in 76% of gastric cancer patients, 77.5% of colonic cancer patients, and 72% of controls. The prevalence of infection was not significantly different in the three groups of subjects sorted according to their HLA-DQA1 or -DQB1 status. Apart from HLA-DQA1* 0201, which was less common in patients with colonic carcinoma than controls, no other HLA-DQA1 and no HLA-DQB1 allele were present at altered frequency in patients with gastric or colonic cancer. Neither anatomical location and histological type of cancer nor the presence of lymph node or distant metastases were significantly associated with specific HLA-DQA1 or -DQB1 alleles or H. pylori infection. Both HLA-DQA1 and -DQB1 genes have a minor, if any, role in H. pylori infection and gastric carcinogenesis.

Mixed tumors, myoepitheliomas, and oncocytomas of the soft tissues are likely members of the same family: a clinicopathologic and ultrastructural study

Four diagnostically unusual soft tissue tumors are presented. All lesions were of consistent size and long duration. Histologically, one lesion was analogous to mixed tumors of the usual sites (i.e., salivary glands), one lesion was totally spindled, and the two other lesions both had oncocytic appearances (epithelioid and spindle biphasic pattern in a case, purely epithelioid in the other). Immunohistochemically, the mixed tumor was positive for vimentin, cytokeratins, S-100 protein, and focally for EMA. The purely spindled tumor exhibited immunoreactivity for vimentin, actins, S-100 protein, EMA (focally), and GFAP. The oncocytic biphasic tumor was positive for mitochondrial antigen, vimentin, and actins. The purely epithelioid oncocytic neoplasm was immunoreactive only for mitochondrial antigen and vimentin. Ultrastructurally, in the epithelial-like portion of the first (mixed) tumor, peripheral arrays of contractile filaments were detected along with well-developed desmosomes. In the second (spindled) case, peripheral contractile filaments and attenuated desmosomes were also seen. In the third case, a huge number of mitochondria, some desmosomes, and actin-type microfilaments were found. In the fourth case, desmosomes and punctate subplasmalemmal densities, in addition to numerous mitochondria, were documented. In all cases an external basal lamina were present, which was discontinuous in the first three cases and almost continuous in the fourth. These tumors were respectively designated as mixed tumor, myoepithelioma of the classic type, myoepithelioma of oncocytic type with biphasic cell architecture, and true oncocytoma. So far, all tumors have followed benign clinical courses (median follow up: 12 months). Comparisons with similar tumors of other sites are drawn, and suggestions for considering all of them as members of the same myoepithelial-derived tumor family are given.