Occult Malignancy in Adult Tonsillectomy for Benign Indication.

OBJECTIVE: National pathology guidelines recommend full pathologic analysis for all adult tonsillectomy specimens. We evaluated the available data on occult malignancy in adult tonsillectomy for benign indication, and created a screening system to reduce the risk of missed malignancies if routine histopathologic examination were to be discontinued. STUDY DESIGN: Retrospective chart review and systematic review of the literature. SETTING: Tertiary care academic hospital and multi-hospital private healthcare system. SUBJECTS AND METHODS: A systematic literature review identified case series of adult tonsillectomy. Retrospective chart review at our institutions from 2000 to 2016 produced an additional case series. The pooled rate of occult malignancy was determined, and re-analyzed using criteria based on preoperative risk factors designed to identify patients requiring full pathologic analysis. The predicted effects of prospective application of the proposed criteria were calculated. Pooled occult malignancy prevalence was estimated. RESULTS: Literature review and our own case series yielded 12,094 total cases. Occult malignancy prevalence in the combined data was 0.033%, representing four occult malignancies. Three out of the four would have been selected for full pathology preoperatively with use of the proposed criteria. Statistical analysis indicates that the predicted frequency of occult malignancy incidence in cases negative for the criteria is 0.01%, or 1/10,000. CONCLUSION: Application of the proposed criteria to adults undergoing tonsillectomy for benign indication identifies a subset of patients with an estimated incidence of occult malignancy similar to that reported for pediatric tonsillectomy, and potentially may permit safe elimination of pathologic analysis of their tonsil specimens. LEVEL OF EVIDENCE: Pooled analysis of case series from the literature and a single institution, level 4.

SATB2 Versus CDX2: A Battle Royale for Diagnostic Supremacy in Mucinous Tumors.

CONTEXT.­: Metastatic mucinous tumors present a diagnostic challenge for pathologists as tumor histomorphology is often nonspecific and optimal immunoprofiles are still under investigation. OBJECTIVE.­: To present a head-to-head comparison of special AT-rich sequence-binding protein 2 (SATB2) and caudal type homeobox 2 (CDX2) expression in a diverse array of primary mucinous tumors. DESIGN.­: SATB2 and CDX2 immunohistochemical stains were performed on whole sections from 44 mucinous colorectal carcinomas and 175 noncolorectal mucinous tumors. A nuclear scoring system measuring intensity (0-3+) and percentage staining (0 = <5%, 1 = 5%-49%, 2 = ≥50%) was implemented, producing an additive histologic score (H-score). RESULTS.­: SATB2 demonstrated acceptable accuracy at low to moderate expression levels (H-scores of 1-4). With these H-score cutoffs, overall accuracy was greater than 90%. In contrast, CDX2's accuracy rivaled that of SATB2 only at an H-score of 5 (89.0%), as its specificity suffered at lower expression levels (<70.0% at H-scores of 1-4). Using a moderate H-score cutoff of 3 or higher, significant differences for both sensitivity and specificity were identified between SATB2 and CDX2 (P = .01 for sensitivity and P < .001 for specificity), though these stains were near equivalent when each was interpreted as positive at its respective optimal H-score (SATB2 ≥ 3 and CDX2 = 5). CONCLUSIONS.­: SATB2 is a more accurate marker of colorectal origin across a variety of expression levels compared with CDX2 when applied to mucinous tumors from a host of primary sites. However, these stains are near equivalent when each is interpreted at its optimal expression level.

A Comprehensive Evaluation of Special AT-rich Sequence-binding Protein 2 (SATB2) Immunohistochemical Staining in Mucinous Tumors From Gastrointestinal and Nongastrointestinal Sites.

Special AT-rich sequence-binding protein 2 (SATB2) is an accurate marker for conventional colorectal carcinoma (CRC), although its sensitivity and specificity in mucinous tumors from the colon and other sites remains unknown. The objective of this study is to evaluate the accuracy of SATB2 expression detected by immunohistochemical assay, as a marker of primary CRC in mucinous adenocarcinomas. SATB2 immunohistochemical stains were performed on whole sections from 63 conventional CRCs (controls), 47 mucinous CRCs (mCRC), and 182 noncolorectal mucinous tumors. SATB2 intensity was scored as 1 to 3 based on the estrogen receptor/progesterone receptor grading system, and the percent positive cells was scored in broad categories as follows: 0 (negative)≤5%, 1=5% to 49%, 2≥50%. An optimal sensitivity/specificity pairing (83% and 95%, respectively) was achieved in the mCRCs when the additive intensity and percent score was ≥3 (ie, intensity score+percent score=total score). Defining this total score (histologic score/"H score") as a "positive" result, the sensitivity of SATB2 for conventional CRC was 98% (62/63) versus 83% (39/47) for mCRCs (P=0.02); whereas 5% (9/182) of all noncolorectal mucinous tumors were considered positive. SATB2 especially demonstrated reduced specificity when applied to mucinous gastroesophageal and breast carcinomas, which showed significant expression in 27% and 9% of cases, respectively. In summary, SATB2 is a less sensitive marker of colorectal origin in mCRC compared with conventional CRC and shows significantly reduced specificity in mucinous gastroesophageal and breast primaries.