Anatomic Abstracts
| Anatomic Abstracts |
|
|
|
September 2010 Editors:
Rapid and accurate differential diagnosis of Burkitt lymphoma and CD10+ diffuse large B-cell lymphoma is imperative because their treatment differs. Recent studies have characterized several antigens that are differentially expressed in these two types of lymphoma. The authors conducted a study to determine whether use of these markers would aid in the differential diagnosis of Burkitt lymphoma versus CD10+ diffuse large B-cell lymphoma (DLBCL) by flow cytometric immunophenotyping (FCI). They identified 23 cases of CD10+ B-cell lymphomas with available cryopreserved samples (13 Burkitt lymphoma and 10 CD10+ DLBCL). The authors performed multiparameter FCI using the antibodies CD18, CD20, CD43, CD44, and CD54, and isotype controls. They detected expression of CD44 and CD54 at a significantly lower level in Burkitt lymphoma compared with CD10+ DLBCL (P=0.001 and P=0.01, respectively). They did not find a significant difference in expression of CD18 and CD43. The authors’ data show that expression of CD44 and CD54 differs significantly between Burkitt lymphoma and CD10+ DLBCL. Schniederjan SD, Li S, Saxe DF, et al. A novel flow cytometric antibody panel for distinguishing Burkitt lymphoma from CD10+ diffuse large B-cell lymphoma. Am J Clin Pathol. 2010;133(5):718–726. Correspondence information not available.
Little is known about the frequency, histopathologic characteristics, and clinical consequences of false-negative prostate biopsies—that is, biopsies classified as benign but containing adenocarcinoma or atypical suspicious glands. The authors conducted a study to evaluate false-negative prostate biopsy in a prostate cancer screening setting. Two urologic pathologists reviewed prostate biopsy sets from 196 participants in a screening trial. The biopsies had been reported as benign at initial diagnosis and then followed by a diagnosis of adenocarcinoma in a subsequent screening round. The pathologists identified ade-nocarcinoma in 19 biopsy cores corresponding to 16 patients (8.2 percent) and atypical small acinar pro-liferations (ASAP) in 24 cores corresponding to 19 patients (9.7 percent). All missed prostate cancers were a Gleason score of six. After correcting for patient selection, the overall false-negative biopsy rate was estimated to be 2.4 percent—1.1 percent for prostate cancer and 1.3 percent for ASAP. Clinicopathologic features at initial biopsy and subsequent prostate cancer diagnosis did not differ between patients with a false-negative or true benign biopsy. The most prominent risk factors for a false-negative diagnosis were a relatively low number of atypcial glands (fewer then 10 glands), intense intermingling with preexistent glands, or lack of architectural disorganization. Another potential pitfall was the presence of prostate cancer variants, as one adenocarcinoma was of foamy gland type and three were of pseudohyperplastic type. The authors concluded that routine examination of at least one level of prostate biopsy sets at high magnification and awareness of histologic prostate cancer variants might reduce the risk of missing or misinterpreting a relevant lesion during prostate biopsy evaluation. Wolters T, van der Kwast TH, Vissers CJ, et al. False-negative prostate needle biopsies: frequency, histopathologic features, and followup. Am J Surg Pathol. 2010;34:35–43. Correspondence: Dr. Tineke Wolters at t.wolters@erasmusmc.nl
Although grading has prognostic significance for many tumor types, a prognostically significant grading system for lung adenocarcinoma has not been established. The authors conducted a study to evaluate histologic characteristics included in tumor grading systems, establish optimal cut-off values that have the strongest association with overall survival, and develop a grading system incorporating the histopathologic characteristics that the authors found to have prognostic significance in patients with lung adenocarcinoma. They studied lung adenocarcinomas from 85 consecutive patients and evaluated the percentage of solid pattern (as a reflection of tumor architecture), degree of cytologic atypia, and mitotic count. The authors found that in univariate analysis, overall survival was associated significantly with gender (P=0.045), age (P=0.0008), tumor status (P<0.0001), lymph node status (P=0.02), solid pattern (P=0.046), and cytologic atypia (P=0.01), but not with mitotic count (P=0.26). On the basis of optimal cut-off values, the authors found that a solid pattern of 90 percent or more and severe cytologic atypia were the best discriminators of worse outcome. A grading score, computed as the sum of the architecture score and cytologic atypia score (2=well differentiated, 3=moderately differentiated, 4=poorly differentiated), was a significant predictor of overall survival in univariate analysis (median overall survival times, 72.4, 39.5, and 8.7 months for well, moderately, and poorly differentiated adenocarcinoma, respectively; P=0.0001). Moreover, grading was an independent predictor of survival in multivariate analysis (P=0.002). The authors concluded that a grading system that incorporates the percentage of solid pattern and degree of cytologic atypia is an independent predictor of survival in patients with lung adenocarcinoma. Barletta JA, Yeap BY, Chirieac LR. Prognostic significance of grading in lung adenocarcinoma. Cancer. 2010;116(3):659–669. Correspondence: Dr. Lucian R. Chirieac at ichirieac@partners.org
Leiomyosarcomas are malignant smooth muscle tumors that occur most commonly in the gynecologic tract and soft tissue. There are different diagnostic criteria of malignancy for smooth muscle tumors arising at gynecologic and soft tissue sites, and they may be managed differently. Determining the primary site of a smooth muscle tumor can be difficult in some cases. Furthermore, it may be difficult to distinguish between malignant and benign gynecologic tract smooth muscle tumors on morphologic grounds. Using a series of tissue microarrays that contained 245 cases of leiomyosarcoma (102 gynecologic) with survival data and 49 cases of uterine leiomyoma, the authors examined the ability of the immune markers estrogen receptor and WT1 to distinguish between leiomyosarcomas of gynecologic and nongynecologic origin. In addition, they examined whether immunostains for p16, p53, and Ki-67 could distinguish between malignant and benign gynecologic smooth muscle tumors. The authors observed estrogen receptor nuclear positivity in three percent and 50 percent of the nongynecologic and gynecologic leiomyosarcomas, respectively (P<0.001). Nuclear WT1 positivity was seen in zero and eight percent of the nongynecologic and gynecologic leiomyosarcomas, respectively (P<0.001). Eighty-seven percent of primary gynecologic leiomyosarcomas and two percent of uterine leiomyomas showed diffuse p16 staining (50 percent or more of cells; P<.001). Twenty-three percent of gynecologic leiomyosarcomas showed p53 immunopositivity (50 percent or more of cells), whereas no leiomyomas were positive for p53 (P<0.001). Sixty-five percent of the gynecologic leio-myosarcomas and none of the leiomyomas exhibited more than 10 percent Ki-67 proliferation index (P<0.001). Diffuse p16 and p53 immunopositivity and high Ki-67 proliferation index, singly or in combination, yielded an overall sensitivity of 92 percent and specificity of 98 percent for distinguishing between gynecologic leiomyosarcomas and leiomyomas and can be used as indicators of malignancy for gynecologic smooth muscle tumors. The authors concluded that although estrogen receptor positivity can be used to support the gynecologic origin of leiomyosarcomas, nuclear WT1 immunostaining is of little use. Lee CH, Turbin DA, Sung YC, et al. A panel of antibodies to determine site of origin and malignancy in smooth muscle tumors. Mod Pathol. 2009,22:1519–1531. Correspondence: Dr. C. B. Gilks at blake.gilks@veh.can Anatomic pathology abstracts editors: Michael Cibull, MD, professor and vice chair, Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington; Melissa Kesler, MD, and Rouzan Karabakhtsian, MD, assistant professors of pathology and laboratory medicine, University of Kentucky College of Medicine; and Megan Zhang, MD, visiting fellow, Division of Dermatopathology, University of California, San Francisco. |
