Chapter 3, Page 3  

BENIGN EPITHELIAL NEOPLASMS, SALIVARY GLAND-LIKE TUMORS, NON-NEOPLASTIC EPITHELIAL PROLIFERATIONS, AND OTHER NON-NEOPLASTIC EPITHELIAL TUMOR-LIKE CONDITIONS GLYCOGEN ACANTHOSIS (GLYCOGENIC ACANTHOSIS) Glycogen acanthosis usually is a white plaque mostly found in the distal esophagus, commonly oriented longitudinally paralleling the longitudinal axis of the esophageal wall (figs. 3-4, 3-5). From an endoscopic standpoint, this lesion is part of the differential diagnosis of endoscopic white plaques in the esophagus: other possibilities include candidiasis, ulcers covered by exudate, and no histologic abnormality, that is, "disappearing white patches." Glycogen acanthosis may be single or multiple, and there is no predictable clinical association with any other condition; they are therefore discovered serendipitously. The only exception was a case of Cowden's syndrome in which mucosal polyps of the stomach were associated with esophageal lesions that appeared to be glycogen acanthoses (20, 22). Glycogen acanthoses are common. In one study, they were found in 15 percent of 160 consecutive esophagoscopies (24). In another study, they were found in 27 consecutive adult autopsies (23). They can be detected by careful radiographic studies, using double contrast views of a well-distended esophagus, as uniform fine nodules, usually less than 3 mm, sometimes producing a cobblestone appearance when multiple, and they are frequently multiple (18, 19). In one radiographic study, they were found in over a fourth of 300 consecutive double-contrast esophagrams (19). In fact, since they are so common, they may even be considered a normal variant (21). The microscopic features are simple and characteristic. The superficial squamous epithelial layers are thicker than normal and contain unusually large cells with pale or clear cytoplasm filled with glycogen (fig. 3-6) (17). The glycogen is best demonstrated by staining the epithelium with the periodic acid-Schiff (PAS) reagent. This stain colors the glycogen granules in the clear cells dark red; pretreating a duplicate slide with diastase (amylase) prior to staining with PAS results in loss of staining, indicating that the material in the cytoplasm of the clear cells is glycogen. Sometimes, it is difficult to tell glycogen acanthosis from normal mucosa when the lesion is less than fully developed, when the top of the epithelium has been stripped during the biopsy process, or when normal mucosa is cut at a bias, so that the superficial layers appear to be unusually thick (see Normal Mucosa in chapter 2 for comparison). In all situations, the diagnosis is questionable and is best avoided if the biopsy is not from an endoscopic plaque.