Metastasis via Peritumoral Lymphatic Dilation in Oral Squamous Cell Carcinoma

Comparative Approach to the Temporo-Spatial Organization of the Tumor Microenvironment

The complex ecosystem in which tumor cells reside and interact, termed the tumor microenvironment (TME), encompasses all cells and components associated with a neoplasm that are not transformed cells. Interactions between tumor cells and the TME are complex and fluid, with each facet coercing the other, largely, into promoting tumor progression. While the TME in humans is relatively well-described, a compilation and comparison of the TME in our canine counterparts has not yet been described. As is the case in humans, dog tumors exhibit greater heterogeneity than what is appreciated in laboratory animal models, although the current level of knowledge on similarities and differences in the TME between dogs and humans, and the practical implications of that information, require further investigation. This review summarizes some of the complexities of the human and mouse TME and interjects with what is known in the dog, relaying the information in the context of the temporo-spatial organization of the TME. To the authors' knowledge, the development of the TME over space and time has not been widely discussed, and a comprehensive review of the canine TME has not been done. The specific topics covered in this review include cellular invasion and interactions within the TME, metabolic derangements in the TME and vascular invasion, and the involvement of the TME in tumor spread and metastasis.

Abnormal Microvasculature in Laryngectomy Mucosal Margins may be Associated with Increased Risk of Fistula

Pharyngocutaneous fistula after laryngectomy is common and significantly increases the morbidity of the procedure. Intraoperative, objective variables that can reliably predict fistula formation would be useful to surgeons deciding how to reconstruct the laryngectomy defect. Retrospective chart review of 50 radiated patients and 10 non-radiated patients who underwent total laryngectomy at a single tertiary care institution. Patients with pharyngocutaneous fistula were selected to ensure a representative sample were available for comparison. All patients had pathology slides available for re-review by a single, blinded pathologist. Margins of both radiated (n = 50) and non-radiated (n = 10) larynges were examined for 7 histologic features, and odds ratios were calculated to assess whether these features were associated with fistula. When evaluating all 60 patients, both telangiectatic capillaries and hyalinized arterioles were associated with fistula (OR 3.72 and 9.21, respectively). Collinearity between the variables was evaluated; findings indicated a high likelihood of having hyalinized arterioles if telangiectatic capillaries were also present (OR 31.67 [3.13, 320.06]). Microvascular changes in radiated tissue have previously been described in other anatomic subsites, but the larynx and pharynx have not been specifically evaluated. Laryngectomy mucosal margins appear to display similar changes, and evidence of this damage may be associated with fistula formation. These features could potentially guide the surgeon to alter the reconstructive technique.