Jennifer B. Kum

P16 expression is not associated with human papillomavirus in urinary bladder squamous cell carcinoma

Squamous cell carcinoma of the urinary bladder is unusual and of unknown etiology. There is a well-established association between human papillomavirus (HPV) infection and the development of cervical and head/neck squamous cell carcinomas. However, the role of HPV in the pathogenesis of squamous cell carcinoma of the urinary bladder is uncertain. The purposes of this study were to investigate the possible role of HPV in the development of squamous cell carcinoma of the urinary bladder and to determine if p16 expression could serve as a surrogate marker for HPV in this malignancy. In all, 42 cases of squamous cell carcinoma of the urinary bladder and 27 cases of urothelial carcinoma with squamous differentiation were investigated. HPV infection was analyzed by both in situ hybridization at the DNA level and immunohistochemistry at the protein level. p16 protein expression was analyzed by immunohistochemistry. HPV DNA and protein were not detected in 42 cases of squamous cell carcinoma (0%, 0/42) or 27 cases of urothelial carcinoma with squamous differentiation (0%, 0/15). p16 expression was detected in 13 cases (31%, 13/42) of squamous cell carcinoma and 9 cases (33%, 9/27) of urothelial carcinoma with squamous differentiation. There was no correlation between p16 expression and the presence of HPV infection in squamous cell carcinoma of the bladder or urothelial carcinoma with squamous differentiation. Our data suggest that HPV does not play a role in the development of squamous cell carcinoma of the urinary bladder or urothelial carcinoma with squamous differentiation. p16 expression should not be used as a surrogate marker for evidence of HVP infection in either squamous cell carcinoma of the urinary bladder or urothelial carcinoma with squamous differentiation as neither HVP DNA nor protein is detectable in these neoplasms.

Mixed Epithelial and Stromal Tumors of the Kidney: Evidence for a Single Cell of Origin With Capacity for Epithelial and Stromal Differentiation

Mixed epithelial and stromal tumors are uncommon biphasic tumors of the kidney, with cystic and solid areas composed of a morphologically diverse stroma, including ovarian-like stroma and an epithelial component with considerable heterogeneity. Little is known about the histogenesis and clonal origins of these tumors. A total of 21 mixed epithelial and stromal tumors of the kidney from female patients who underwent radical or partial nephrectomies were examined. The epithelial and stromal components, and also adjacent non-neoplastic renal parenchymal tissues were separately laser microdissected from sections prepared from formalin-fixed and paraffin-embedded tissues for X chromosome inactivation analysis. Nineteen of the 21 tumors were informative. Seven of these informative cases showed random X chromosome inactivation pattern in both epithelial and stromal components of mixed epithelial and stromal tumors of the kidney. Nonrandom inactivation of the X chromosome was found in 12 of 19 informative tumors. The same pattern of nonrandom inactivation of the X chromosome was seen in both epithelial and stromal components in all 12 of the tumors with nonrandom X chromosome inactivation. Our data support the theory that the stroma and epithelium arise from a common cell of origin.

Molecular genetic evidence supporting the origin of somatic-type malignancy and teratoma from the same progenitor cell.

Occasionally, testicular teratomas have been observed to occur in association with somatic-type malignancies. The latter may be seen in the primary germ cell tumor or, more commonly, in metastases after chemotherapy. The molecular-genetic relationship between the teratoma and the somatic-type malignancy is uncertain. We examined 27 pairs of teratoma and somatic-type malignancies in metastatic lesions. Interphase fluorescence in situ hybridization (FISH) analysis for 12p overexpression and i(12p) was performed on formalin-fixed, paraffin-embedded specimens. In addition, we compared the pattern of allelic loss between the teratoma and the somatic-type malignancy using 4 microsatellite DNA markers (D1S508, interferon-&agr;, D13S317, and D18S543). A laser capture microdissection technique was used to procure separate tumor components. The somatic-type malignancies included adenocarcinoma (13), primitive neuroectodermal tumor (5), sarcoma not otherwise specified (5), squamous cell carcinoma (1), chondrosarcoma (1), and rhabdomyosarcoma (2). Twenty-one of 27 tumor pairs (78%) showed a similar pattern of overexpression of 12p and/or i(12p) in both components. Two of the 27 (7%) tumor pairs showed i(12p) only in the teratomatous component, and 4 of the 27 (15%) tumor pairs showed no abnormalities of chromosome 12p by interphase FISH. Eight of the 12 (67%) tumor pairs analyzed had identical patterns of loss of heterozygosity in both the teratoma and the somatic-type malignancy. Four of the 12 (33%) paired cases showed additional allelic loss at the interferon-&agr; locus in the somatic-type malignant component only. Our data show that the somatic-type malignancies that develop in germ cell tumors have the same genetic alterations, detectable by FISH and loss of heterozygosity studies, as in the corresponding teratoma. These findings support that the somatic-type malignancies within metastases and the teratomas are clonally related and likely derived from a common progenitor cell. Interphase FISH can be performed on formalin-fixed, paraffin-embedded tissue and is a sensitive method for detecting 12p overexpression and i(12p), thus aiding in establishing the germ cell origin of somatic-type malignancies in this context.

The spectrum of histopathologic findings in vesical diverticulum: implications for pathogenesis and staging

Diverticula are saccular evaginations of urinary bladder mucosa that are encountered in all age groups with a prevalence of 1% to 10%. Intradiverticular neoplasms pose diagnostic and management challenges. The aim of this study was to document the common morphologic changes and neoplasms found in a large series of adult and pediatric vesical diverticula. A total of 174 diverticula from 133 patients were reviewed including 48 pediatric (mean age, 7.1 years) and 85 adult (mean age, 63.93 years); 92% were male. Of the 85 nonneoplastic cases, prominent morphologic findings included significant chronic inflammation (59), granulomatous inflammation including foreign body giant cell reaction (6), acute inflammation (7), squamous metaplasia (9), cystitis glandularis (10), and nephrogenic metaplasia (2). The pediatric cases showed no malignancy. Thirty-three of the 48 neoplastic cases had high-grade urothelial carcinoma, 4 had carcinoma in situ, 7 had low-grade papillary urothelial carcinoma, 2 had primary squamous cell carcinoma, 1 had primary melanoma, and 1 had urothelial dysplasia. Nine of the neoplastic cases had variant morphology. Diverticula from 31 cases were involved by primary tumors, of which 6 had coexisting intravesical neoplasia (3 had carcinoma in situ with invasion elsewhere). In 19 of 33 high-grade urothelial carcinomas, infiltration into adjacent fat was noted. Seven of these cases arose within diverticula. Diverticula may harbor neoplasms, most commonly urothelial carcinoma. Attenuation of the muscle layer associated with diverticulum formation may facilitate tumor invasion into peridiverticular soft tissues. It is emphasized that pT2 stage should be eliminated to avoid the confusion in staging these neoplasms.

Clear cell renal cell carcinoma with a syncytial-type multinucleated giant tumor cell component: implications for differential diagnosis ☆

A component of syncytial-type multinucleated tumor giant cells is uncommon in clear cell renal cell carcinoma, and the histogenesis, incidence, and clinical implications of this finding are not well understood. We retrieved 13 such tumors from our pathology archives in patients with a median age of 60years, comprising 1.5% of clear cell renal cell carcinomas. Stage was typically pT4 or pT3 (each 38%). Microscopically, all tumors included a component of low-grade clear cell renal cell carcinoma with usual features. Syncytial-type giant tumor cells possessed voluminous cytoplasm, usually granular and eosinophilic, and numerous nuclei similar to those of the mononuclear tumor cells. Transition between areas of mononuclear and multinucleated cells was sometimes abrupt. Other findings included necrosis (77%), hyaline globules (46%), emperipolesis (46%), and intranuclear cytoplasmic invaginations (23%). Immunohistochemical staining typically revealed both mononuclear and multinucleated cells to be positive for carbonic anhydrase IX, CD10, epithelial membrane antigen, vimentin, and cytokeratin AE1/AE3 and negative for β human chorionic gonadotropin, TFE3, cathepsin K, cytokeratin 7, cytokeratin 20, HMB45, CD68, smooth muscle actin, and S100. Most patients with available information (7/9) were alive with metastatic disease at the most recent follow-up. Syncytial-type giant cells are an uncommon finding associated with aggressive clear cell renal cell carcinomas. Despite the unusual appearance of this tumor component, its immunoprofile supports an epithelial lineage and argues against trophoblastic, osteoclast-like, or histiocytic differentiation. Reactivity for typical clear cell renal cell carcinoma antigens facilitates discrimination from giant cells of epithelioid angiomyolipoma or other tumors, particularly in a biopsy specimen or a metastatic tumor.

Bladder Diverticulum: Clinicopathologic Spectrum in Pediatric Patients

Urinary bladder diverticula are a relatively rare finding in both the adult and pediatric population. Their presence in the adult population has long been associated with the development of urothelial carcinoma within the lesion. Our goal is to analyze a relatively large pediatric patient population with urinary bladder diverticula to expand the body of knowledge on the associated clinical symptomatology, congenital syndromes associated with the entity, and treatment methods and to further investigate if there is any reason to suspect malignant transformation within the pediatric population. A search for pediatric patients (0–19 years of age) from 1990 to 2011 revealed 47 patients with 60 diverticula within the specified age range. Clinical records and histologic slides for all cases were pulled for review, and statistical analysis was performed on the results. The most common findings were vesicoureteral reflux (68%), recurrent urinary tract infection (55%), and hydronephrosis (40%). Fourteen of 47 (30%) patients had an associated congenital syndrome/malformation. Diverticular size range was 0.5–10 cm with a mean of 2.56 cm. No patient was found to have overt malignancy or dysplastic changes within the diverticula or bladder at the time of pathologic evaluation. High association with recognizable clinical symptoms and additional urinary tract abnormalities leads to early identification and treatment. A sizable percentage of those found to have bladder diverticula within the pediatric population will have a congenital syndrome. No association with malignancy is seen within pediatric bladder diverticula; it is an extremely unlikely event in these young patients.

Nephrogenic adenomas in pediatric patients: a morphologic and immunohistochemical study of 21 cases.

Similar to nephrogenic adenomas in adults, those in children are rare benign lesions that often occur in the setting of previous surgery or chronic irritation of the urinary tract. These lesions often present with hematuria and/or as polypoid or papillary lesions on cystoscopy, which may indicate malignancy. We sought to evaluate the various patterns of nephrogenic adenoma occurring in the pediatric population and better characterize the immunophenotype of these lesions. We reviewed 21 cases of nephrogenic adenomas from urinary bladder biopsies of 16 patients. Most patients had a history of urinary bladder augmentation with recurrent urinary stones and urinary tract infections. Many cases presented as a papillary or polypoid mass on cystoscopy. The most common morphologic patterns are papillary, tubulocystic, and a mixed pattern of papillary and tubulocystic, followed by cystic and tubular. On immunostaining, PAX-2, PAX-8, CK7, and MUC-1 provided the most diffuse and intense positive reactivity for nephrogenic adenoma, whereas CD10 and P504S were focal and lesser in intensity when positive. p63 and PAX-5 were consistently negative. We conclude that, although rare in children, nephrogenic adenoma should be included in the differential diagnosis of papillary/polypoid lesions in the urinary tract, especially in the context of previous surgery, chronic irritation from recurrent urinary tract infections, or stones. The immunohistochemistry profile of nephrogenic adenomas in our study also provides evidence that these are derived from distal renal tubular cells. In difficult cases, an immunohistochemical panel consisting of cytokeratin 7, PAX-2, PAX-8, and MUC-1 may be useful.

Signet ring cell carcinoma of the testis: clinicopathologic and molecular evidence for germ cell tumor origin--a case report.

Development of a somatic-type malignancy from a mixed germ cell tumor is a rare but recognized event and typically represented by sarcoma or, less commonly, by carcinoma. This phenomenon is generally believed to result from progression of a teratomatous component. In many cases, because of intermingling of other germ cell tumor components, the diagnosis is apparent; however, in rare cases, metastatic carcinoma to the testis or a novel primary tumor may be a diagnostic consideration. In this study, we report the clinicopathologic, immunohistochemical, and molecular features of a 53-year-old man, whose testicular tumor was composed entirely of signet ring cells, mimicking metastatic carcinoma. Subsequent retroperitoneal lymph node dissection revealed metastatic deposits composed of teratoma and yolk sac tumor, in addition to signet ring cell carcinoma. Fluorescence in situ hybridization for abnormalities of chromosome 12p revealed the presence of i(12p) in both the teratoma and signet ring cell carcinoma in the metastasis and in signet ring cells in the testis, supporting a common germ cell origin. Our report indicates that signet ring carcinoma cells in an orchiectomy specimen, although usually strongly suggestive of metastatic adenocarcinoma from a primary tumor in another organ, may be a primary testicular neoplasm of germ cell tumor origin. This is the first report of testicular signet ring cell carcinoma of germ cell tumor derivation.

Paraganglion cells stain positively for OCT4: A potential pitfall in assessing retroperitoneal lymph node dissection specimens for germ cell tumour metastasis

preparation. The aspirate was cellular, and showed dyshesive malignant cells with round–ovoid nucleoli, scant cytoplasm and inconspicuous nucleoli (Figure 1A). The cells showed the following immunoprofile: CD45, CD3, CD4 and CD5 were positive; CD8, CD20, CD10 and Bcl2 were negative. Occasional cells showed CD99 positivity. The Ki67 proliferative index was 80–90%. The morphology and immunophenotype were highly suggestive of T lymphoblastic lymphoma. However, unexpectedly, TdT immunocytochemistry was negative (Figure 1B). Further sampling of the lesion was advised, in order to make a definitive diagnosis. Biopsy of the mass was carried out subsequently, obtaining two 18 G cores of tissue. Cores showed infiltration by small–medium-sized lymphoid cells with high nuclear:cytoplasmic ratio, stippled chromatin and occasional nucleoli (Figure 1C). Immunohistochemistry demonstrated similar results to those obtained on the FNA specimen except that, on this occasion, TdT staining of the malignant cells was strongly positive (Figure 1D). A diagnosis of T lymphoblastic lymphoma was made and the patient was commenced on treatment accordingly. A literature search was carried out to help identify any reason why TdT immunocytochemical staining might be negative in a case which, in all other respects, fitted the criteria for lymphoblastic lymphoma. A study was identified in which cell dehydration and alcohol fixation were shown to denature TdT. The authors examined smears from the bone marrow or peripheral blood of patients with acute lymphoblastic leukaemia in two ways. First, air-dried smears were fixed with methanol, acetone or ethanol –acetic acid. Secondly, non-dehydrated cells were fixed with glutaraldehyde and treated with non-ionic detergents (compounds NP 40 and Brij 56) for membrane permeabilization. It was found that methanol reduced TdT positivity significantly compared to detergents. Acidified ethanol staining was inferior even to methanol. The authors suggested that denaturation artefacts in the evaluation of TdT immunocytochemistry could be avoided by the use of non-dehydrated cells fixed with glutaraldehyde and treated with non-ionic detergents. Similar false-negative immunocytochemical results with alcohol-based fixatives have also been shown with regard to other antibodies (S100, Hep Par 1 and gross cystic disease fluid protein-15), and it is postulated that leaching out of proteins is the cause. However, air-drying and alcohol fixation remain one of the main methods of preparing FNA cytology samples. FNA sampling is used frequently for diagnosis of soft tissue masses in which the differential diagnosis includes lymphoma. In particular, lymphoblastic lymphoma is one of the main differential diagnoses in the case of a mediastinal mass. We believe it is important to be aware of this potential pitfall whereby a false-negative TdT result may be obtained in a case of lymphoblastic lymphoma, as it has the potential to lead to delayed or misdiagnosis of this aggressive disease.

Müllerian Adenosarcoma of the Urinary Bladder: Clinicopathologic and Immunohistochemical Features With Novel Genetic Aberrations

Micro‐Abstract We report, to our knowledge, the first case of Müllerian adenosarcoma arising in the urinary bladder with extensive clinicopathologic, immunohistochemical, and molecular analyses. Because of the tendency of low‐grade Müllerian adenosarcomas to recur and/or develop stromal overgrowth, discerning this diagnostic entity from benign extrauterine processes (such as endometriosis) has important diagnostic and clinical implications. Background: Müllerian adenosarcoma is a biphasic neoplasm most commonly occurring in the uterus and less frequently of the ovary. It has been rarely described to occur in other sites such as peritoneum and liver. Patients and Methods: In this study, we report the clinicopathologic, immunohistochemical and molecular features of a primary Müllerian adenosarcoma of the urinary bladder in a 62‐year‐old woman. To our knowledge, this is the first report of detailed pathologic characterization of Müllerian adenosarcoma primary to the urinary bladder in the literature. Results: Light microscopy showed a biphasic epithelial and stromal tumor with benign‐appearing glands surrounded by densely cellular endometrial‐type stroma that is densely cellular with increased mitotic figures. The stroma surrounding the glands was more cellular than the intervening areas, which were more loose and edematous. Immunohistochemistry staining revealed positive staining for Pax‐2/8 within the glands, for positive CD10 and WT‐1 within the spindle cell stroma, and for estrogen and progesterone receptors in both. Staining for desmin, GATA3, p63, and human papillomavirus was negative. Molecular analyses identified mutations in protein kinase B E17K, fms related tyrosine kinase 3 D835N, KRAS proto‐oncogene, GTPase G12D, and HRAS proto‐oncogene, GTPase G12S. These novel molecular aberrations have yet to be reported in the medical literature. X chromosome inactivation analysis revealed a clonal pattern in the stromal component and a nonclonal pattern in the epithelial component. Currently, the patient is disease/recurrence‐free after regular follow‐up of approximately 84 months. Conclusion: This case represents, to our knowledge, the first reported diagnosis of Müllerian adenosarcoma arising in the urinary bladder with extensive clinicopathologic, immunohistochemical, and molecular analyses.