Ming Tse Sung

Sinonasal undifferentiated carcinoma and nasopharyngeal-type undifferentiated carcinoma: two clinically, biologically, and histopathologically distinct entities.

Sinonasal undifferentiated carcinoma (SNUC) is a rare aggressive neoplasm arising in the nasal cavity and paranasal sinuses. Primary sinonasal nasopharyngeal-type undifferentiated carcinoma (PSNPC) is an even rarer tumor that has not been adequately reported. Both tumors have been reported to be associated with Epstein–Barr virus (EBV). We studied the clinicopathologic features and EBV status of 36 SNUC and 13 PSNPC patients from Taiwan, an EBV endemic area. The median age of SNUC patients was 53 years (range 20–76 years), with a male/female ratio of approximately 2:1. Five patients had histories of previous nasopharyngeal carcinoma treated with irradiation 6–26 years earlier. The most common locations were nasal cavity and ethmoid sinus. Orbital and intracranial invasion and distant metastasis were frequent findings. The median survival was 10 months. All 36 tumors were negative for EBER-1 by in situ hybridization. The median age of PSNPC patients was 58 years (range 36–75 years), with a male/female ratio of approximately 2:1. The most common location is nasal cavity. Eight patients achieved disease-free survival. Eight tumors had the morphology of lymphoepithelioma, whereas significant inflammatory infiltrate was not detected in the other five tumors. All 13 tumors were positive for EBER-1 by in situ hybridization. Because of the difference in the relation with EBV, prognosis, and response to radiotherapy, SNUC and PSNPC should be considered as two entirely different entities. The most important criteria for PSNPC are vesicular nuclei, syncytial pattern, spindle cells, and absence of necrosis.

Divergent pathway of intestinal metaplasia and cystitis glandularis of the urinary bladder

Intestinal metaplasia has been proposed to be a precursor lesion of adenocarcinoma in the urinary bladder. CDX2 is a transcription factor that is encoded by a homeotype gene that plays an essential role in the differentiation and proliferation of intestinal epithelial cells. Hepatocyte-specific antigen (Hep) has also been shown to be a useful marker of intestinal metaplasia. Tissues from 46 patients, including 22 cases of intestinal metaplasia of the urinary bladder, 11 cases of typical cystitis glandularis, and 13 cases containing both lesions, were selected and immunohistochemical stains for CDX2, Hep, cytokeratin 20 (CK20), and cytokeratin 7 (CK7) were performed. Nuclear staining for CDX2 was observed in 29 of 35 (83%) cases of intestinal metaplasia of the urinary bladder. In contrast, nuclear staining for CDX2 was not observed in any case of typical cystitis glandularis; however, seven of 24 (29%) cases showed aberrant cytoplasmic expression in a mean of 37% of cells. CK20 was expressed in 28 of 35 (80%) cases of intestinal metaplasia, but was observed in only one of 24 (4%) cases of cystitis glandularis in 15% of cells. CK7 was expressed in only six of 35 (17%) cases of intestinal metaplasia, whereas expression of CK7 was observed in all cases (100%) of typical cystitis glandularis with a mean percentage of positively staining cells of 63%. The mean percentages of positively staining cells in intestinal metaplasia with CDX2, CK20, and CK7 were 55, 49, and 53%, respectively. All examples of both intestinal metaplasia and typical cystitis glandularis were uniformly negative for Hep. In the urinary bladder, intestinal metaplasia and typical cystitis glandularis have sharply contrasting immunoprofiles. Additionally, the absence of Hep staining in intestinal metaplasia of the urinary bladder, despite its morphologic resemblance to normal colonic mucosa and intestinal metaplasia in other organs, may signify the presence of unique metaplastic pathways in the urinary bladder.

Urothelial carcinoma with an inverted growth pattern can be distinguished from inverted papilloma by fluorescence in situ hybridization, immunohistochemistry, and morphologic analysis.

Inverted papilloma of the urinary bladder and urothelial carcinoma with an inverted (endophytic) growth pattern may be difficult to distinguish histologically, especially in small biopsies. The distinction is important as these lesions have very different biologic behaviors and are treated differently. We examined histologic features and undertook immunohistochemical staining and UroVysion fluorescence in situ hybridization (FISH) to determine whether these methods could aid in making this distinction. We examined histologic sections from 15 inverted papillomas and 29 urothelial carcinomas with an inverted growth pattern. Each tumor was stained with antibodies to Ki-67, p53, and cytokeratin 20. In addition, each tumor was examined with UroVysion FISH for gains of chromosomes 3, 7, and 17 and for loss of chromosome 9p21 signals. None of the inverted papillomas stained positively for Ki-67 or for cytokeratin 20. Only 1 of 15 inverted papillomas stained positively for p53. By contrast, 66%, 59%, and 59% of urothelial carcinomas with an inverted growth pattern stained positively for Ki-67, p53, and cytokeratin 20, respectively. Only 3 of the urothelial carcinomas stained negatively for all 3 immunohistochemical markers. UroVysion FISH produced normal results for all cases of inverted papilloma. By contrast, 21 of 29 cases (72%) of urothelial carcinoma with an inverted growth pattern demonstrated chromosomal abnormalities typical of urothelial cancer and were considered positive by UroVysion FISH criteria. Morphologic features, as well as immunohistochemical stains (including stains for Ki-67, p53, and cytokeratin 20) and/or UroVysion FISH can help to distinguish inverted papilloma from urothelial carcinoma with an inverted growth pattern.

Radial distance of extraprostatic extension measured by ocular micrometer is an independent predictor of prostate-specific antigen recurrence: A new proposal for the substaging of pT3a prostate cancer.

Extraprostatic extension is an unfavorable prognostic factor for prostate cancer. Consequently, it has been assigned to pT3a in the current 2002 tumor, lymph node, metastasis staging system. The aim of our study is to analyze the extent of extraprostatic extension by 8 quantitative methods and to determine which is best for substaging of pT3a tumors. We studied 83 patients with extraprostatic extension after radical prostatectomy for clinically localized prostatic adenocarcinoma. The extent of extraprostatic extension was evaluated using 8 quantitative methods. Univariate and multivariate analyses were performed to determine which measurement best predicts prostate-specific antigen (PSA) recurrence. In the univariate analysis, the radial distance of extraprostatic tumor measured by ocular micrometer was associated with PSA recurrence (P=0.02). No significant association was observed between PSA recurrence and other measurements of extraprostatic extension, including focal versus established extraprostatic extension using Epsteins criterion, focal versus established extraprostatic extension using Wheelers modified criterion, the number of extraprostatic neoplastic glands, unilateral versus bilateral involvement, circumferential length of extraprostatic tumor, unifocal versus multifocal involvement, and volume of extraprostatic tumor. In the multivariate analysis, radial distance remained an independent predictor of PSA recurrence (hazard ratio, 2.4; 95% confidence interval, 1.12-5.01; P=0.02). The radial distance of the extraprostatic extension measured by ocular micrometer is an independent prognostic factor for pT3 prostate cancer. Two-year and 4-year PSA recurrence-free survival was 62% and 35%, respectively, for those patients with radial distance <0.75 mm, as compared with 35% and 18%, respectively, for those with radial distance ≥0.75 mm. We recommend reporting this parameter routinely for radical prostatectomy specimens. The strength of its prognostic value for PSA recurrence makes it a potential criterion for incorporation into a future tumor, lymph node, metastasis staging system.

Histogenesis of clear cell adenocarcinoma in the urinary tract: evidence of urothelial origin.

Purpose: Clear cell adenocarcinoma in the urinary tract is a rare entity with an appearance resembling its counterpart in the female genital tract. Although several theories have been proposed about its origin, its exact histogenesis has remained uncertain. Experimental Design: We integrated molecular genetic evaluation by fluorescence in situ hybridization and X-chromosome inactivation with conventional morphologic and immunohistochemical analyses in 12 patients with clear cell adenocarcinomas in the urinary tract. Results: Concurrent urothelial carcinoma or urothelial carcinoma in situ was present in six cases (50%) and foci of cystitis glandularis were observed in four cases (33%). Neither intestinal metaplasia nor Müllerian component was identified in any case. Cytoplasmic expression of α-methylacyl-CoA racemase was demonstrable in 10 of 12 tumors (83%). Moderate to diffuse immunostaining for cytokeratin 7 was identified in all 12 tumors (100%), whereas only 3 of 12 (25%) tumors showed positive immunostaining for cytokeratin 20. Focal uroplakin III staining was seen in 6 of 12 tumors (50%). In five cases (42%), focal to moderate CD10 immunoreactivity was observed. Immunostains for OCT4 and CDX2 were completely negative in all tumors. In UroVysion fluorescence in situ hybridization assays, all tumors displayed chromosomal alterations similar to those commonly found in urothelial carcinoma. Identical patterns of nonrandom X-chromosome inactivation in concurrent clear cell adenocarcinoma and urothelial neoplasia were identified in two informative female cases. Conclusions: Our findings support an urothelial origin for most clear cell adenocarcinomas of the urinary tract, despite their morphologic resemblance to certain Müllerian-derived tumors of the female genital tract.

Primary mediastinal seminoma: A comprehensive assessment integrated with histology, immunohistochemistry, and fluorescence in situ hybridization for chromosome 12p abnormalities in 23 cases

Accurate diagnosis of mediastinal seminoma is critical because of its favorable response to radiation therapy and/or cisplatin-based chemotherapy. Immunohistochemical staining for OCT4 has recently been validated as a powerful tool for detecting gonadal seminoma. However, discrepancies between the genetic alterations and immunoprofiles of mediastinal and testicular seminomas have been reported, raising the question of whether techniques that are useful in the diagnosis of gonadal seminoma are applicable to its mediastinal counterpart. The present study was conducted to evaluate the morphologic and immunohistochemical characteristics and chromosomal abnormalities of 12p in 23 primary mediastinal seminomas and to compare their applicability as diagnostic tools. Dual-color fluorescence in situ hybridization (FISH) analyses for chromosome 12p and immunostains for OCT4, c-kit, placental-like alkaline phosphatase, CD30, and a panel of cytokeratins, including cytokeratin AE1/AE3 (AE1/3), high molecular weight cytokeratin (34βE12, HMWCK), CAM5.2, cytokeratin 7 (CK7), cytokeratin 20 (CK20), and epithelial membrane antigen were performed. Lymphocytic infiltration was found in all 23 cases (100%). The incidence of other histologic characteristics were as follows: fibrous septa/stroma (21 cases, 91%), prominent tumor cell nucleoli (21 cases, 91%), clear tumor cell cytoplasm (20 cases, 87%), distinct tumor cell borders (20 cases, 87%), granulomatous inflammation (17 cases, 74%), cellular pleomorphism (10 cases, 43%), necrosis (8 cases, 35%), prominent cystic change (2 cases, 8%), intercellular edema (1 case, 4%), and syncytiotrophoblasts (1 case, 4%). The mean mitotic count was 4.4 (range 0 to 16) per 10 high-power fields. Moderate to strong nuclear OCT4 staining was identified in all 23 cases (100%). Seventeen tumors (74%) showed membranous expression of c-kit, with variable staining intensity and percentages. Weakly to moderately intense immunostaining for placental-like alkaline phosphatase was identified in 10 cases (43%) with occasional background staining artifact. The incidences of positive staining were 43% for AE1/3, 39% for HMWCK, 48% for CAM5.2, 39% for CK7, and 9% for epithelial membrane antigen, respectively. In most cases, these epithelial markers highlighted only a small proportion of tumor cells with variable intensities. Immunostaining for CD30 and CK20 was completely negative in all seminomas. Twenty-two seminomas (96%) revealed chromosome 12p abnormalities, including 12p amplification in 20 cases (87%) or i(12p) in 15 cases (65%). Lymphocytic infiltration is the most common histologic feature observed in primary mediastinal seminoma and both OCT4 immunostain and FISH for 12p abnormalities can be very helpful in diagnosing mediastinal seminoma. The intense staining pattern of OCT4 and the high sensitivity of FISH make them superior to other auxiliary diagnostic utilities for detecting seminoma. In addition, the incidences of cytokeratin expression of primary mediastinal seminoma are similar to those of its gonadal counterpart and pathologists must exercise caution in the interpretation of epithelial markers in mediastinal neoplasms.

Telomere Shortening and Chromosomal Abnormalities in Intestinal Metaplasia of the Urinary Bladder

Purpose: Although intestinal metaplasia is often found in association with adenocarcinoma of the urinary bladder, it is unclear whether intestinal metaplasia of the bladder is a premalignant lesion. Telomere shortening has recently been implicated in epithelial carcinogenesis. We used quantitative fluorescent in situ hybridization (FISH) to measure telomere length and UroVysion FISH to detect cytogenetic abnormalities in urinary bladder specimens with intestinal metaplasia. Experimental Design: Paraffin-embedded tissue blocks from 34 patients with intestinal metaplasia of the urinary bladder were evaluated. Twelve of the 34 patients had coexistent cystitis glandularis, and telomere length was measured in these lesions for comparison. Tissue sections were prepared and hybridized with a telomere-specific peptide nucleic acid probe. Quantitative FISH on interphase nuclei was used to assess telomere signal intensity. Additional sections were hybridized with centromeric probes for chromosomes 3, 7, and 17 and a locus-specific probe 9p21. Multicolor FISH was used to analyze for cytogenic abnormalities in the interphase nuclei of intestinal metaplasia. Results: In all 34 cases, reduced average telomere signal intensity was observed in the nuclei of intestinal metaplasia cells compared with adjacent control nuclei to produce a mean relative intensity of 48.5% (P < 0.0001). When cystitis glandularis was present, significant differences in the telomere-specific signal intensity existed between cystitis glandularis and normal cells (P = 0.0005) and between cystitis glandularis and intestinal metaplasia cells (P = 0.0015). Three of the 34 cases showed chromosomal gains in the UroVysion FISH assay. Conclusions: Our findings indicate that intestinal metaplasia in the urinary bladder is associated with significant telomere shortening relative to telomere length in adjacent normal urothelial cells. These lesions also occasionally showed cytogenetic abnormalities associated with telomere shortening. Our findings support the hypothesis that intestinal metaplasia of the urinary bladder is a precursor lesion to and could be a marker in the development of adenocarcinoma of the urinary bladder.

FGFR3 and TP53 mutation analysis in inverted urothelial papilloma: incidence and etiological considerations

Urothelial papillomas and low-grade urothelial carcinomas have shown a high incidence of fibroblast growth factor receptor 3 (FGFR3) mutations and are associated with a favorable prognosis. The association of FGFR3 mutations with inverted papillomas is less known. We analyzed 20 cases of inverted papilloma in the urinary tract. Mutations of FGFR3 (exons 7, 10, and 15) and TP53 genes were evaluated by DNA sequencing in these cases. Point mutations of the FGFR3 gene were identified in 45% (9 of 20) of inverted papillomas with four cases exhibiting mutations at multiple exons. Seven cases had exon 7 mutations containing R248C, S249T, L259L, P260P, and V266M. Two cases had exon 10 and 15 mutations including A366D, H412H, E627D, D641N, and H643D; five cases had N653H. The most frequent mutation was identified at R248C. None of the inverted papillomas exhibited mutations in TP53. During a mean follow-up of 78 months, none had recurrence or developed urothelial carcinoma. These findings support the concept that low-grade and low-stage urothelial neoplasms arise in a background of molecular changes that are distinctly different from the molecular changes of high-grade and high-stage urothelial cancers.

Retroperitoneal seminoma in limited biopsies: morphologic criteria and immunohistochemical findings in 30 cases.

The incidence of retroperitoneal seminoma is much less than that of its gonadal counterpart. Accurate diagnosis of retroperitoneal seminoma is critical, because it carries an excellent prognosis due to its favorable response to radiation therapy and/or cisplatin-based chemotherapy. However, correctly diagnosing a retroperitoneal seminoma may be challenging, especially when the biopsy material is limited. The present study was conducted to evaluate histologic findings and immunohistochemical staining patterns in biopsy specimens of retroperitoneal seminoma and to compare their utility as diagnostic tools. Thirty biopsy specimens of retroperitoneal seminoma were assessed for histologic characteristics and immunohistochemical expression of OCT4, c-kit, placental-like alkaline phosphatase, and cytokeratin AE1/AE3. The clinical information, morphologic features, and staining intensities and the percentages of positively staining tumor cells were analyzed. The mean age of patients was 38 years. Lymphocytic infiltration and nucleolar prominence in tumor cells were found in all 30 cases (100%). The incidence of other histologic characteristics were as follows: fibrous septa/stroma in 80% (24 cases), clear tumor cell cytoplasm in 70% (21 cases), tumor necrosis in 60% (18 cases), cellular pleomorphism in 53% (16 cases), granulomatous inflammation in 50% (15 cases), distinct cell borders in 46% (14 cases), intercellular edema in 23% (7 cases), and syncytiotrophoblasts in 3% (1 case). The mean mitotic count was 3 (range 0 to 15) per 10 high-power fields. All 30 cases (100%) of retroperitoneal seminoma revealed moderate to strong nuclear OCT4 staining in more than 50% of tumor cells. Twenty-one cases (70%) showed membranous expression of c-kit by tumor cells, with moderate to strong staining intensity in most cases. Variable degrees of staining for placental-like alkaline phosphatase were identified in 23 cases (77%) with occasional background staining artifact. Six cases (20%) displayed a positive cytokeratin AE1/AE3 staining pattern with weak to moderate intensity. In conclusion, the most common histologic findings in limited biopsy specimens of retroperitoneal seminoma were lymphocytic infiltration and nucleolar prominence in tumor cell nuclei. OCT4 immunostaining, with its superior sensitivity and easy interpretation compared with other markers, is a powerful tool for confirming the diagnosis of retroperitoneal seminoma.