Functional loss of tumor suppressor genes detected by loss of heterozygosity, but not driver mutations, predicts aggressive lymph node status in papillary thyroid carcinoma.

BACKGROUND: Recognizing aggressive tumor biology is essential to optimizing patient management for papillary thyroid carcinomas (PTC). Aggressive lymph node (ALN) status is one feature that influences decision-making. We evaluated genomic deletions in regions of tumor suppressor genes, detected by loss of heterozygosity (LOH) analysis, to understand causal alterations linked to thyroid cancer aggressiveness and to serve as a molecular diagnostic biomarker for ALN status. METHODS: We analyzed 105 primary PTC enriched for patients with ALN (64% with, 36% without). We also analyzed 39 positive lymph nodes (79% with, 21% without ALN). LOH was determined using a panel of 25 polymorphic microsatellite alleles targeting 10 genomic loci harboring common tumor suppressor genes. Additionally, ThyGeNEXT® and ThyraMIR® assays were performed. RESULTS: LOH was detected in 43/67 primary PTC from patients with ALN status, compared with only 5/38 primary PTC without ALN (minimal metastatic burden) (P=0.0000003). This is further supported by post hoc analyses of paired primary and metastatic samples. Paired samples from patients with ALN are more likely to harbor LOH, compared to the ALN negative group (P=0.0125). Additionally, 12/31 paired samples from patients with ALN demonstrated additional or different LOH loci in metastatic samples compared to the primary tumor samples. No association was seen between ALN and mutational, translocation, or microRNA data. CONCLUSIONS: LOH detected in primary PTC significantly predicts ALN status. Analysis of paired primary and metastatic samples from patients with / without ALN status further supports this relationship. The acquisition of LOH at additional loci is common in lymph nodes from patients with ALN status. SIMPLE SUMMARY: A subset of patients with papillary thyroid carcinoma (PTC) will develop recurrent disease. One known predictor of recurrence is the American Thyroid Association category "Aggressive Lymph Node" (ALN) disease, considering metastatic burden. Loss of heterozygosity (LOH) - chromosomal loss in regions of tumor suppressor genes - has yet to be investigated as a possible mechanism driving ALN status in PTC. The ability to predict ALN status prior to surgery can guide the extent of surgery and postoperative treatment options. We found that paired samples from patients with ALN are more likely to harbor LOH, compared to patients without ALN disease. 38% of patients with ALN demonstrated additional or different LOH loci in metastatic samples compared to the primary tumor samples. LOH complements current molecular analysis of thyroid cancer when searching for evidence of aggressive biology.

Frozen Section Analysis in Head and Neck Surgical Pathology: A Narrative Review of the Past, Present, and Future of Intraoperative Pathologic Consultation.

Frozen section has remained the diagnostic gold standard for intraoperative pathological evaluation of surgical margins for head and neck specimens. While achieving tumor-free margins is of utmost importance to all head and neck surgeons, in practice, there are numerous debates and a lack of standardization for the role and method of intraoperative pathologic consultation. This review serves as a summary guide to the historical and contemporary practice of frozen section analysis and margin mapping in head and neck cancer. In addition, this review discusses current challenges in head and neck surgical pathology, and introduces 3D scanning as a groundbreaking technology to bypass many of the pitfalls in the current frozen section workflow. The ultimate goal for all head and neck pathologists and surgeons should be to modernize practices and take advantage of new technology, such as virtual 3D specimen mapping techniques, that improves the workflow for intraoperative frozen section analysis.

A staged approach to oromandibular reconstruction using the iliac crest free flap in the setting of bilateral failed fibula free flaps.

BACKGROUND: While a single-stage free-flap reconstruction is the preferred approach for oromandibular defects, a multistaged approach may be necessary in rare cases. These patients can still be effectively restored with functional and aesthetic improvements. METHODS: We report two cases with a history of bilateral failed fibula free flaps. We detail the multistaged reconstruction to repair these complex defects and discuss the considerations when planning such procedures. RESULTS: Both patients successfully underwent a staged reconstruction with an iliac crest osteocutaneous flap following either a rectus abdominis or pectoralis major myocutaneous flap. CONCLUSION: Oromandibular reconstruction is an expected outcome in the contemporary management of oral cavity cancer and osteoradionecrosis. However, complications do occur and can be devastating. In cases of bilateral failed fibula free flaps, a staged approach is a favorable option. Moreover, the iliac crest provides an important reconstructive option with the documented potential for implant born dental rehabilitation.

WPOI-5: Accurately Identified at Intraoperative Consultation and Predictive of Occult Cervical Metastases.

BACKGROUND: Frozen section analysis of oral cancer specimens is ideal for assessing margin distances and depth of invasion (DOI); the latter impacts intraoperative decisions regarding elective neck dissection (END). Here, we show that intraoperative determination of worst pattern of invasion (WPOI), specifically WPOI-5, has a high level of accuracy. This relates to our demonstration herein that WPOI-5 predicts occult cervical metastases (OCM) for pT1 oral squamous carcinoma (OSC). METHODS: The presence of OCM was correlated with WPOI in 228 patients with primary T1/T2/cN0 OSC undergoing resection and END. Concordance between intraoperative and final pathology WPOI determination was assessed on 51 cases of OSC. RESULTS: WPOI-5 predicts OCM in pT1 patients, compared with WPOI-4/WPOI-3 (p < 0.0001). Most pT1 WPOI-5 tumors had DOI of 4-5 mm (24/59 or 40.7%). Only two pT1 WPOI-5 tumors had DOI < 4 mm (3.0 and 3.5 mm). If END were performed in this pT1 cohort for all WPOI-5 OSC patients regardless of DOI, OR all OSC patients with DOI ≥ 4 mm regardless of WPOI, then no OCM would be missed (p = 0.017, 100% sensitivity, 29% specificity, 77% positive predictive value, 23% negative predictive value). With respect to intraoperative WPOI-5 determination, the accuracy, sensitivity, and specificity was 92.16, 73.33, and 100.0%, respectively. CONCLUSIONS: DOI ≥ 4 mm is the dominant predictor of OCM. For the rare WPOI-5 OSC with DOI < 4 mm, it is reasonable to suggest that surgeons perform END. WPOI-5 may be accurately determined intraoperatively. As microscopic instruction is needed to accurately assess WPOI-5, a teaching link is included in this manuscript.

Extratumoral invasion: A unique phenomenon of aggressive recurrent oropharyngeal squamous cell carcinoma.

BACKGROUND: Oropharyngeal squamous carcinomas cause significant morbidity and mortality. Poor prognosticators include lymphovascular and perineural invasion. Extratumoral phenotypes of these histologic findings confer worse prognoses. METHODS: We report eight cases of recurrent oropharyngeal cancer with diffuse extratumoral lymphovascular invasion (ELVI) or extratumoral perineural invasion (EPNI) and review the existing literature. RESULTS: On salvage resection for recurrence following primary radiation or chemoradiation, six patients manifested ELVI and two showed EPNI. These patterns conferred difficulty with complete surgical clearance; final pathologic analysis demonstrated positive margins for all eight patients. The six patients with ELVI were p16+ and the two with EPNI were p16-. Currently, two patients are deceased and six patients are alive at an average follow-up of 17.4 months. Of the six living patients, 2 have a new recurrence and are in hospice while 4 have no evidence of disease. CONCLUSIONS: ELVI and EPNI have received little consideration in the literature as unique histopathologic features of oropharyngeal squamous carcinoma. We present the first series on these adverse extratumoral features in recurrent disease. We call attention to these unique histologic features in the setting of recurrent oropharyngeal cancer to encourage others to track the results of therapeutic intervention and to identify successful strategies for treatment.

Utilizing 3D head and neck specimen scanning for intraoperative margin discussions: Proof of concept of our novel approach.

BACKGROUND: The current standard of documenting and communicating frozen section margin results is inefficient. We present a novel method of generating 3D digital models of gross tumor specimens to more clearly visualize histopathological margin results. METHODS: Fifty-five head and neck specimens were scanned and virtually "inked" using 3D software. These 3D specimen maps were displayed in the operating room to provide the surgeon with a real-time specimen-to-defect relationship by which further resections could be guided. RESULTS: Margin results were reported within an average of 34 min using the proposed workflow. The scanner rendered accurate models of specimens that exceeded 3.0 × 3.0 × 3.0 cm. Critical specimen features to consider were size, color, textural complexity, and the presence of discernible anatomic landmarks. CONCLUSIONS: Optical 3D scanning technology can improve the quality of head and neck margin documentation and the efficiency with which results are communicated between the pathologist and surgeon.

Cuneiform (cuniculatum) variant of oral squamous cell carcinoma revisited: Presentation of two cases and literature review of a rare entity.

BACKGROUND: Oral carcinoma cuniculatum (OCC) is a rare, locally aggressive tumor, which tends to invade underlying bone. We present two cases of OCC, one demonstrating invasion of the mandible and the other limited to the tongue. METHODS: An 87-year-old male presented with a right-sided buccogingival lesion. Biopsy results led to a diagnosis of verrucous hyperplasia, which was later revised to OCC. Additionally, a 94-year-old female presented with a left lateral tongue lesion. A biopsy showed in-situ and invasive keratinizing squamous cell carcinoma that was later defined as a soft tissue OCC. RESULTS: Following surgical resection, the diagnosis of OCC was established in both patients. We provide a comprehensive literature review of OCC in the context of both case presentations. CONCLUSIONS: OCC is a rare entity, which has a tendency to be misdiagnosed. We emphasize the importance of recognizing the common features of OCC in order to aid in accurate diagnosis.