Importance of Stromal Desmoplasia in Staging Early Esophageal Adenocarcinoma on Endoscopic Mucosal Resection Specimens
Monika Tripathi, Andrea Grin, Catherine Streutker. St. Michael's Hospital, Toronto, ON, Canada
Background: One of the important challenges in assessing endoscopic mucosal resection specimens is to provide accurate depth of invasion and presence or absence of submucosal invasion. This distinction is crucial as submucosal invasion generally indicates a need for esophagectomy, but may be very difficult in cases where submucosal glands or vessels are not present to define the presence of submucosal tissue. It is a common perception that presence of stromal desmoplasia usually signifies submucosal invasion and that it is absent or poorly developed at the intramucosal stage of invasion. However, to date no studies have documented the incidence and frequency of stromal desmoplasia in esophageal adenocarcinomas.
Design: In this study we retrospectively reviewed a cohort of 60 endoscopically resected cases of early esophageal adenocarcinomas to evaluate tumor differentiation & depth of invasion with presence or absence of stromal desmoplasia. Histologically, desmoplastic response was defined by presence of large stromal cells with increased loose extracellular matrix. If present, desmoplasia was graded as mild, moderate or extensive by three gastrointestinal pathologists. Based on the depth of invasion, the cases included in the study were sub-classified as- M1/2(lamina propria or superficial muscularis mucosae invasion, n=17), M3 (invasion between the layers of duplicated and true muscularis mucosae, n=7), M4 (true muscularis mucosae invasion, n=17) & SM1 (early submucosal invasion, n=23).
Results: Patient age range was 39-90 years(M: F= 51:9). 91% of submucosal invasive tumors had at least focal desmoplasia (Mild 47.7%, Moderate 26%, Extensive 17.3%). Within the intramucosal tumors, 40 % had a mild to moderate degree of desmoplasia (Mild 24%, Moderate 16%). All of these were deep mucosal tumors (M3/M4) with moderate to poor differentiation. None of the superficial intramucosal tumors (M1/2) showed any desmoplasia and none of the deep intramucosal tumors (M3/4) had extensive desmoplasia.
Conclusions: Stromal desmoplasia is not conclusively limited to the submucosal invasive tumors. Moderate to poorly differentiated deep intramucosal tumors may also develop a degree of stromal desmoplasia. The finding of desmoplasia can therefore not be used as an absolute indicator of submucosal invasion, as it may be present in intramucosal lesions and focal or absent in some tumours definitively invading submucosal tissue. These findings may aid in the assessment of depth of invasion which is a deciding factor for further surgical therapy for patients with early esophageal carcinomas.
Monday, March 4, 2013 1:00 PM
Poster Session II # 114, Monday Afternoon