Brian F. Skinnider

Distribution of cytokeratins and vimentin in adult renal neoplasms and normal renal tissue: potential utility of a cytokeratin antibody panel in the differential diagnosis of renal tumors.

Adult renal epithelial neoplasms (RENs) comprise several distinct clinicopathologic entities with potential prognostic and therapeutic differences. Individual cases can show overlapping morphologic features, necessitating the use of ancillary methods. The purpose of this study was to determine the diagnostic utility of cytokeratin (CK) subtype expression pattern in a wide range of adult RENs. RENs (including clear cell [conventional] renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, renal oncocytoma, collecting duct carcinoma (CDC), renal medullary carcinoma (RMC), urothelial carcinoma, metanephric adenoma (MA), tubulocystic carcinoma (TC) (also known as low-grade collecting duct carcinoma), and mucinous tubular and spindle cell carcinoma) were immunostained for CK subtypes (CK5/CK6, 7, 8, 13, 14, 17, 18, 19, 20), high molecular weight CKs 1, 5, 10, 14 (HMWCK), and vimentin (Vim). The expression pattern of normal kidney was also examined and correlated with RENs. Although there is some overlap, subtypes of RENs show distinctive CK expression profiles that may be useful in several differential diagnostic settings. Clear cell RCCs typically showed a restricted expression pattern of CK8, CK18 and Vim. Papillary RCCs typically expressed CK7, CK8, CK18, CK19, and Vim and could be distinguished from MA (CK7−). Chromophobe RCCs were typically CK7+, CK8+, CK18+, and Vim−, and could be distinguished from oncocytomas (typically CK7−). In oncocytomas, nonspecific staining of unblocked endogenous biotin is a potentially significant diagnostic pitfall. CDC, RMC, and TC demonstrated similar CK expression profiles (with the exception of HMWCK expression limited to CDC), supporting a close relationship between these entities. A panel of CK5/CK6, CK17, and Vim may be helpful in distinguishing CDC (typically CK5/CK6−, CK17−, Vim+) and urothelial carcinoma (typically CK5/CK6+, CK17+, Vim−). In conclusion, CK expression patterns may be helpful in several differential diagnostic situations when dealing with adult RENs.

Bcl-6 and Bcl-2 protein expression in diffuse large B-cell lymphoma and follicular lymphoma: Correlation with 3q27 and 18q21 chromosomal abnormalities

The bcl-2 gene on chromosome 18 at q21 and the bcl-6 gene on chromosome 3 at q27 are both highly regulated during B-cell differentiation and show an inverse relationship of expression in the normal secondary lymphoid follicle. The objective of this study was to investigate the relationship between bcl-2 and bcl-6 protein expression and the relationship between protein expression and the corresponding chromosomal alterations in malignant lymphomas, including those associated with the germinal center. Expression of bcl-2 and bcl-6 proteins was studied in 55 cases of diffuse large B-cell lymphoma (DLBCL) and 21 cases of follicular lymphoma (FL), and the results correlated with the presence of t(14;18) and 3q27 abnormalities in a subset of 52 cases with cytogenetic analysis. These cases were selected to represent a spectrum of nodal and extranodal lymphomas, including those with and without a t(14;18). It was shown that the neoplastic cells in 71% of DLBCLs and 100% of FLs expressed bcl-6 protein. Expression of bcl-6 was seen more frequently in diffuse large B-cell lymphomas with large noncleaved morphology compared with immunoblastic morphology (82% v 27%, P = .0015), but failed to correlate with 3q27 abnormalities. Thirty-eight percent of cases with 3q27 abnormalities were bcl-6 protein negative, whereas 85% of cases without a 3q27 abnormalities were bcl-6 protein positive. Expression of bcl-2 protein was shown in 51% DLBCLs (nodal v extranodal, 71% v 30%, P = .012). bcl-2 protein was expressed in 89% of FLs with t(14;18), in contrast to 25% of FLs without t(14;18) (P = .016). In DLBCL and FL with t(14;18), the most common pattern of expression was bcl-2+/bcl-6+. In lymphomas without t(14;18), there was not an inverse relationship between bcl-2 and bcl-6 protein expression. In conclusion, these data suggest that mechanisms other than gene rearrangements can deregulate bcl-2 and bcl-6 expression in lymphomas, and there does not appear to be an inverse relationship between these two proteins as seen in the normal germinal center.

Immunohistochemical analysis of mucinous tubular and spindle cell carcinoma and papillary renal cell carcinoma of the kidney : Significant immunophenotypic overlap warrants diagnostic caution

Mucinous tubular and spindle cell carcinoma, a rare, recently described distinctive subtype of renal cell carcinoma, may have some morphologic similarities to the more common papillary renal cell carcinoma, particularly the basophilic (type 1) tumors with prominent solid growth pattern. Tumor circumscription, compact tubular architecture, focal papillations, mucin production and foam cells (features seen in both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma), as well as spindle cell morphology, have resulted in some cases sent to us in consultation with a question of possible sarcomatoid papillary renal cell carcinoma. In this study, tissue microarrays with triplicate samples each from 27 mucinous tubular and spindle cell carcinomas and 20 papillary renal cell carcinomas were created to simulate experience in renal biopsy specimens. From immunohistochemistry (IHC) data, published in the contemporary literature, a panel consisting of α-methylacyl-CoA racemase (AMACR), cytokeratin 7 (CK7), epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), CD10, high molecular weight cytokeratin (HMWK), and c-kit was designed to test its utility in differential diagnosis. The immunoreactivity in mucinous tubular and spindle cell carcinoma was AMACR 93%, CK7 81%, EMA 95%, RCC Ma 7%, CD10 15%, HMWK 15%, and c-kit 5% and in papillary renal cell carcinoma was AMACR 95%, CK7 65%, EMA 88%, RCC Ma 25%, CD10 80%, HWMK 15%, and c-kit 18%. This largest study to date on IHC of mucinous tubular and spindle cell carcinoma dispels the specificity of AMACR for papillary renal cell carcinoma among the RCC subtypes. The histogenesis of mucinous tubular and spindle cell carcinoma from the distal nephron continues to be debatable, as our study showed the expression of the proximal convoluted tubule-related marker AMACR among these tumors. Thus, in tumors with predominant compact tubular growth and focal papillary architectures, careful attention to the presence of a low-grade spindle cell population may be helpful in the distinction of mucinous tubular and spindle cell carcinoma, as the key immunohistochemical stains for papillary renal cell carcinoma are also expressed in this subtype of renal cell carcinoma.

Transformation to Aggressive Lymphoma in Nodular Lymphocyte-Predominant Hodgkin's Lymphoma

PURPOSE Prior observations suggest a higher risk of transformation of nodular lymphocyte-predominant Hodgkins lymphoma (NLPHL) to aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL), than in classical Hodgkins lymphoma. We evaluated the frequency of transformation in all patients diagnosed with NLPHL at the British Columbia Cancer Agency with long-term follow-up. PATIENTS AND METHODS The Lymphoid Cancer Database of the British Columbia Cancer Agency was searched to identify all patients diagnosed with NLPHL between 1965 and 2006. After pathologic review, 95 patients with NLPHL were confirmed. Results Patients with NLPHL had the following characteristics at diagnosis: median age of 37 years, 73% male, and 68% stage I or II disease. With a median follow-up time for living patients of 6.5 years (range, 2.5 to 33 years), 13 patients (14%) experienced transformation to aggressive lymphoma (median time to transformation, 8.1 years; range, 0.35 to 20.3 years). The actuarial risk of transformation to aggressive lymphoma was 7% and 30% at 10 and 20 years, respectively. Transformation was more likely in patients with initial splenic involvement (P = .006) at the time of diagnosis of NLPHL. The 10-year progression-free and overall survival rates in patients with transformed lymphoma were 52% and 62%, respectively. CONCLUSION The risk of transformation in patients with NLPHL to DLBCL is substantial and underappreciated. Because transformation can occur years after the primary diagnosis of NLPHL, long-term follow-up of these individuals is necessary to accurately estimate the risk of development of secondary DLBCL.

Expression of alpha-methylacyl-CoA racemase (P504S) in nephrogenic adenoma: a significant immunohistochemical pitfall compounding the differential diagnosis with prostatic adenocarcinoma.

α-Methylacyl-CoA racemase (AMACR, P504S) has recently been shown to be a useful marker for the diagnosis of prostatic adenocarcinoma and a potential aid in its distinction from its many mimics, one of which is the benign lesion, nephrogenic adenoma (NA). The goal of this study was to assess the expression of AMACR in NA by immunohistochemistry, as well as other potentially useful markers, high-molecular-weight cytokeratin clone 34βE12, p63, and prostate-specific antigen (PSA). AMACR was expressed in 4/4 NAs involving the prostatic urethra and underlying stroma, and in 3/16 NAs involving the bladder. The prostatic cases showed circumferential granular cytoplasmic AMACR expression of at least moderate intensity, in >75% of tubules in 3 cases and in <10% of tubules in the remaining case. The AMACR-positive cases in the bladder typically showed focal weak noncircumferential staining of the tubules and stronger staining of the cells lining the papillae. 34βE12 staining was observed in 1/4 prostatic NAs and 4/16 bladder NAs, typically in a cytoplasmic pattern in a minority of cells. p63 and PSA were negative in all cases. Our data indicate that NA of the prostatic urethra commonly expresses AMACR and lacks basal cell–specific markers, making it not only a potential morphologic mimic of prostatic adenocarcinoma but also a significant immunohistochemical mimic as well. Awareness of NA as a significant pitfall in the diagnosis of prostatic adenocarcinoma and careful examination of hematoxylin and eosin–stained sections remains the key to the correct diagnosis, which can be supported by a negative PSA stain.

CHOP-R therapy overcomes the adverse prognostic influence of BCL-2 expression in diffuse large B-cell lymphoma

BCL-2 protein expression correlates with shorter survival in patients with diffuse large B cell lymphoma (DLBCL) who are treated with CHOP chemotherapy. We report a retrospective analysis of the prognostic significance of BCL-2 status in patients who received CHOP with the addition of rituximab (CHOP-R) for DLBCL. Patients over 15 years of age with de novo, HIV negative DLBCL, without CNS involvement, and known BCL-2 protein status were identified from the BCCA Lymphoid Cancer Database. BCL-2 tumour positivity was defined as over 50% of tumour cells with BCL-2 protein expression. 140 patients who received CHOP-R were analysed. The majority (59%) of patients were over 60 years of age. Disease stage distribution was limited (22%) and advanced (78%). BCL-2 protein expression was observed in 90 (64%) cases. IPI score was similar in both BCL-2 positive and negative cases. Median follow-up time for living patients is 40 months. BCL-2 status did not predict for either progression-free or overall survival. IPI score was predictive for progression-free survival but not overall survival. The addition of rituximab to CHOP chemotherapy negates the adverse prognostic influence of BCL-2 protein expression on progression free and overall survival in DLBCL.

Treating limited-stage nodular lymphocyte predominant Hodgkin lymphoma similarly to classical Hodgkin lymphoma with ABVD may improve outcome.

The appropriate therapy for limited-stage nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is unclear. In contrast to classical Hodgkin lymphoma (CHL), chemotherapy is often omitted; however, it is unknown whether this impacts the risk of relapse. Herein, we compared the outcome of patients with limited-stage NLPHL treated in an era in which ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy was routinely incorporated into the primary therapy to an earlier era in which radiotherapy (RT) was used as a single modality. Using the British Columbia Cancer Agency Lymphoid Cancer Database, 88 patients with limited-stage NLPHL (stage 1A/1B or 2A, nonbulky disease < 10 cm) were identified. Treatment followed era-specific guidelines: before 1993, (n = 32) RT alone; and 1993 to present (n = 56), ABVD-like chemotherapy for 2 cycles followed by RT with the exception of 14 patients who received ABVD chemotherapy alone. Most patients were male (75%) with stage I disease (61%). In an era-to-era comparison, the 10-year time to progression (98% vs 76% P = .0074), progression-free survival (91% vs 65% P = .0024), and OS (93% vs 84%, P = .074) favored the ABVD treatment era compared with the RT alone era. Treating limited-stage NLPHL similarly to CHL may improve outcome compared with the use of radiation alone.

Expression Analysis of Kidney-specific Cadherin in a Wide Spectrum of Traditional and Newly Recognized Renal Epithelial Neoplasms: Diagnostic and Histogenetic Implications

Kidney-specific cadherin (Ksp-cad) is a membrane-associated cell adhesion glycoprotein expressed by the distal nephron tubular cells in its later developmental stages. Chromophobe renal cell carcinoma and renal oncocytoma are reported to be variably positive for Ksp-cad with some studies suggesting a discriminatory role for Ksp-cad. Immunoreactivity in other tumors with granular eosinophilic cytoplasm including clear cell and papillary renal cell carcinomas needs to be clearly elucidated and its expression in emerging novel and other unusual renal epithelial neoplasm subtypes including tumors with uncertain histogenesis is not yet known. In this study, we performed a detailed immunohistochemical analysis for Ksp-cad in a broad range of 136 renal epithelial neoplasms. Reactivity with Ksp-cad was observed in the following tumors: chromophobe renal cell carcinoma [23/25 (92%), diffuse (>50% of tumor cells)] positivity and membranous characteristically accentuating the “plant cell-like” histomorphology of the typical (clear) type, renal oncocytoma [15/20 (75%), usually diffuse staining with predominantly membranous accentuation], papillary renal cell carcinoma [5/17 (29%) all focal to moderate, eosinophilic type or type 2-3/7 (43%), basophilic type or type 1-2/10 (20%)], Xp11 translocation carcinoma [1/4 (25%), diffuse positivity] and clear cell renal cell carcinoma [6/36 (17%) all focal, clear cell renal cell carcinoma with prominent eosinophilic cells 1/7 (14%)]. Immunoreactivity was higher when evaluating whole histologic sections than with tissue microarrays for both chromophobe renal cell carcinoma (100% vs. 60%) and renal oncocytoma (100% vs. 55%). No immunoreactivity was observed in mucinous tubular and spindle cell carcinomas (0/23), high-grade collecting duct carcinomas (of Bellini) (0/3), renal medullary carcinomas (0/2), and urothelial carcinomas (0/6). Our study documents the immunoreactivity of Ksp-cad in the range of contemporarily classified renal epithelial neoplasms. The findings argue against the use of Ksp-cad in differentiating chromophobe renal cell carcinoma and renal oncocytomas and further support their relationship to the distal nephron. Ksp-cad may be helpful in distinguishing these two tumor types from clear cell renal cell carcinoma with prominent eosinophilic cells particularly in cases with limited tissue samples (ie, needle core biopsy). In the similar diagnostic setting, caution must be exercised, however, in differentiating chromophobe renal cell carcinoma and renal oncocytoma from the eosinophilic variant of papillary renal cell carcinoma as moderate expression of Ksp-cad may be observed in papillary renal cell carcinoma. The histogenesis of mucinous tubular and spindle cell carcinoma remains debatable as this tumor does not express Ksp-cad, which is highly expressed normally in the thick ascending loop of Henle and the distal convoluted tubules. In conclusion, Ksp-cad is a useful tumor type associated marker for distinguishing chromophobe renal cell carcinoma and renal oncocytoma from the wide range of nonintercalated cell-related adult renal epithelial neoplasms; addition of this marker to a panel comprised of other histologic subtype-associated markers may greatly facilitate histologic subclassification of adult renal epithelial neoplasms.

Anaplastic large cell lymphoma: a clinicopathologic analysis.

The clinicopathologic features of anaplastic large cell lymphoma (ALCL) are reviewed. ALCL is a heterogeneous group of tumours, and histologic examination alone is not adequate in providing useful prognostic information. However, using a combination of clinical, phenotypic, and genotypic features, several distinct clinicopathologic entities have been identified. A subset of ALCL as presently defined is characterized by a balanced translocation, t(2;5)(p23;q35), resulting in a novel fusion protein (NPM‐ALK) that can be readily detected by immunohistochemical methods using antibodies against the ALK protein. Detection of ALK protein, along with other methods for demonstrating the t(2;5), has assisted in identifying a distinct biologic entity within the heterogeneous group of ALCL with significant prognostic implications. It is important to separate these from cases of ALK‐negative ALCL, which have a poorer prognosis, and cases of primary cutaneous ALCL, which have an excellent prognosis. Copyright

Follicular non-Hodgkin lymphoma grades 3A and 3B have a similar outcome and appear incurable with anthracycline-based therapy

BACKGROUND The revised World Health Organization (WHO) classification maintains a histological grading system (grades 1-3) for follicular lymphoma (FL) and subdivides grade 3 into 3A (FL3A) and 3B (FL3B) subtypes. Optimal therapy of FL grade 3 and its potential curability with anthracycline-based chemotherapy remain uncertain. PATIENTS AND METHODS We carried out a retrospective population-based analysis evaluating the clinical characteristics and outcome of FL3A and FL3B as strictly defined by WHO diagnostic criteria. Using the BC Cancer Agency Lymphoid Cancer Database, 161 patients with FL grade 3 were identified and, following detailed pathology review, composed of 139 with FL3A and 22 with FL3B. RESULTS Patients with FL3B had a higher overall International Prognostic Index (IPI) score than FL3A patients (P = 0.03), though no significant difference in individual IPI risk factor frequencies was noted. More patients with FL3B received front-line anthracycline-containing chemotherapy (82% versus 36%, P ≤ 0.001). With median follow-up of 45 months, no difference in disease-specific survival (P = 0.74) or overall survival (OS) (P = 0.87) was found between FL3A and FL3B and no survival curve plateau was observed. Analysis limited to FL3A patients showed no OS advantage with front-line anthracycline use (P = 0.33). CONCLUSION Using strict diagnostic criteria, there appears to be no difference in outcome between patients with FL3A and FL3B and no evidence of curability with anthracycline-based therapy.