Case 4 -

Giant Fibrovascular Polyp of the Esophagus David A. Owen University of British Columbia Vancouver, British Columbia, Canada

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History: The patient is a man aged 62 who presented with episodes of intermittent upper airway obstruction. At endoscopic examination the larynx appeared normal. As the endoscope was passed into the upper esophagus the patient "burped" then took a deep breath. A large polypoid lesion emerged from the upper esophagus and was aspirated into the trachea. Fortunately, the airway was not completely obstructed and with the aid of a laryngoscope the polyp was removed from the trachea and returned to the esophagus. At surgery the following day, the polyp was excised. The laboratory received two polypoid masses each measuring 4.5X4.0cm. They were covered by squamous epithelium. Description of Slide: The polyp is covered by non-dysplastic squamous epithelium. A shallow ulcer is noted at the tip of the polyp. At the base there is inflamed granulation tissue and atypical spindle cells. These are mitotically inactive and appear regenerative. The major portion of the head of the polyp is composed of loose connective tissue containing fibroblasts and prominent vessels, both veins and arteries. Adipose tissue is present throughout the polyp but this is lobulated rather than being encapsulated. Lipoblasts are not identified. A scattering of mixed inflammatory cells is noted. Case 4 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 4 - Figure 1 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 2 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 3 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 4 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 5 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 6 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 7 Origninal slides showing the gross, low power views and high power views of the esophageal polyp C Case 4 - Figure 8 Additional images of polyp Case 4 - Figure 9 Additional images of polyp Case 4 - Figure 10 Additional images of polyp Case 4 - Figure 11 Lipoblasts and cells from a well- differentiated liposarcoma, for comparative purposes Case 4 - Figure 12 Lipoblasts and cells from a well- differentiated liposarcoma, for comparative purposes Case 4 - Figure 13 Lipoblasts and cells from a well- differentiated liposarcoma, for comparative purposes Differential Diagnosis: There is a wide range of lesions of the upper esophagus that may become polypoid. They include: carcinoma, neuroendocrine tumor, squamous papilloma, inflammatory polyp, leiomyoma, leiomyosarcoma, GIST, granular cell tumors, rhabdomyosarcoma and Kaposi's sarcoma, osteochondroma and nerve sheath tumors. The majority of these diagnoses are easily eliminated from consideration by a relatively superficial gross and microscopic examination. However, a more detailed inspection is required to exclude the possibility of a well-differentiated liposarcoma (atypical lipomatous neoplasm) also called ALN/WDL. A careful microscopic search for lipoblasts and lipoblast-like cells is suggested. If cells of this type are present an immunostain for MDM2 and CDK4 may be helpful in positively identifying lipoblasts and distinguishing them from their mimics. Well differentiated liposarcomas at this location may recur if incompletely excised but do not metastasize. Final Diagnosis: Giant Fibrovascular Polyp of the Esophagus Discussion: Giant fibrovascular polyp (GFVP) of the esophagus was first brought to pathologic attention by Stout and Lattes [1] in 1957. Since then there have been several single or double case reports but few large series have been published. The clinical and pathologic features of these polyps can be pieced together from these various reports. GFVP is typically encountered in middle aged men although there is a broad age range (18-88 years) at presentation. Very occasional cases have been reported in women. In the majority of cases (70%) they present with dysphagia and weight loss. In a minority of cases there is regurgitation of the polyp into the oropharynx or mouth with or without respiratory obstruction. Rare cases have been described where the patient has complete respiratory obstruction and asphyxiates [8, 9]. In spite of the large size of the polyps, they can be quite difficult to demonstrate radiologically. This is largely because they are covered by smooth esophageal non-keratinizing squamous epithelium that often remains un-ulcerated. With only a short broad stalk present the polyps may closely appose the esophageal wall so that swallowed contrast medium is prevented from surrounding the lesions and delineating them. In some cases where there is a large proximal polyp the lower esophagus may be compressed and narrowed producing an achalasia-like radiologic picture. Manometry may demonstrate loss of esophageal peristalsis and a failure of relaxation of the lower esophageal sphincter, thus reinforcing a misleading diagnosis of achalasia [11]. CT and MRI are the most useful imaging modalities [7]. These techniques can identify the presence of a polyp stalk and demonstrate a heterogeneous appearance within the polyp head. They can also demonstrate the characteristic finding of many large stromal vessels. As the name of these polyps indicates, they are large. At presentation, a majority measure >5.0cm in greatest dimension. An average size is 13.3cm in length and 3.8cm in diameter [11]. Obviously, smaller examples do exist but they may be asymptomatic and only discovered incidentally. Polyps are generally located in the proximal cervical esophagus, although similar lesions have been identified in the hypopharynx [13]. Typically, the polyps are covered by intact esophageal squamous epithelium although some examples may be ulcerated at the tip particularly where this extends into the distal esophagus. This ulceration may be an effect of acid regurgitation rather than localized mucosal ischemia. The composition of the head and stalk of the polyps is heterogeneous. Lobulated adipose is a major component but this is not encapsulated as it would be in a lipoma. Also present are fibrous tissue, myxoid tissue and prominent ecstatic vessels of various calibers. Chronic inflammation may be encountered but is often sparse. There may also be focal hemorrhage. This mixture of tissues within the lesion has given rise to various names such as lipoma, fibrolipoma, and fibromyxoma. Lesions occurring in the hypopharynx have been termed "Giant Hypopharyngeal Atypical Lipomatous Tumor" [13]. As with many polypoid fibrous lesions 'atypical" stromal cells may be encountered. Immunohistochemical analysis of histologically typical GFVPs does not appear to offer additional diagnostic information. Most reported cases of GFVP have been cured by local excision although occasional examples have recurred following an incomplete removal [12]. Rarely, squamous cell carcinoma can complicate FVGP [10]. Also, there have been occasional examples described where well differentiated liposarcoma may mimic GFVP [11], Although no deaths from well-differentiated liposarcoma have been recorded they will recur if incompletely excised.. Distinguishing atypical reactive histiocytes from lipoblasts is not always easy. In one recent case [13] immunohistochemical positivity for MDM2 and CDK4 together with FISH amplification of the MDM2 locus were required to confirm a diagnosis of liposarcoma. The pathogenesis of GFVP is unknown. However, the likeliest origin is from an out pouching of submucosal tissue into the lumen of the esophagus. This occurs in an area of the esophagus referred to as the Laimer-Heckman triangle where the bulk of the underlying crico-pharyngeal muscle is relatively deficient. One a small protrusion is formed, peristaltic action will further enlarge the polyp. Mechanical factors at this level of the GI tract are such that the polyp can become extremely large before obstructive symptoms occur. Fatty tissue is normally seen in the submucosal layers of the GI tract and when polyps of any type occur this may undergo hyperplasia. The best example of this is fatty infiltration of the ileo-cecal valve. Generally it is low-grade and easily diagnosable as being non-neoplastic. However, in some patients enlargement of the valve can be dramatic and the fatty enlargement may result in a polypoid configuration. In this situation, imaging studies may be confusing and the enlargement may be confused with a carcinoma. Mucosa overlying the valve may ulcerate giving rise to intestinal bleeding that also may give rise to suspicion of malignancy [14]. With extreme fatty enlargement a polypoid valve can lead to intussusception. References: Stout AP, Lattes R. Tumors of the esophagus. Atlas of tumor pathology, Series 1, Fascicle 20. Washington DC: Armed Forces Institute of Pathology; 1957. Patel J, Kieffer RW, Martin M, et al. Giant fibrovascular polyp of the esophagus. Gastroenterology 1984;87: 953-6. Penagini R, Ranzi T, Velio P, et al. Giant fibrovascular polyp of the oesophagus: report of a case and effects on esophageal function. Gut 1989;30:1624-9 Avezzano EA, Fleischer DE, Merida MA, et al. Giant fibrovascular polyps of the esophagus. Am J Gastroenterol 1990;85:299-302. Behar PM, Arena S, Marrangoni AG. Recurrent fibrovascular polyp of esophagus. Am J Otolaryngol 1995;16:209-12. Wu MH, Chuang CM, Tseng. Giant intraluminal fibrovascular polyp of the esophagus. Hepatogastroenterology 1998;45:2115-6. Ascenti G, Racchiusa S, Mazziotti S, et al. Giant fibrovascular polyp of the esophagus CT and MR findings. Abdom Imaging 1999;24:109-10. Fries MR, Galindo RL, Flint PW, et al. Giant fibrovascular polyp of the esophagus: A lesion causing upper airway obstruction and syncope. Arch Pathol Lab Med 2003;127:485-7. Sargent RL, Hood IC. Asphyxiation caused by giant fibrovascular polyp of the esophagus. Arch Pathol Lab Med 2006;130:725-7 Caceres M, Steeb G, Wilkes SM, et al. Large pedunculated polyps originating in the esophagus and hypopharynx. Ann Thorac Surg 2006;81:393-6 Jakowski JD, Wakely PE. Rhabdomyomatous well-differentiated liposarcoma arising in giant fibrovascular polyp of esophagus. Ann Diagn Pathol 2009;13:263-8. Lee SY, Sivanandran R, Lim DT, et al. Recurrent giant fibrovascular polyp of the esophagus. World J Gastroenterol 2009;15: 3697-700. McQueen C, Montgomery E, Dufour B, et al. Giant hypopharyngeal lipomatous tumor. Adv Anat Pathol 2010;17:38-41 Greenwald RA, Morris SJ, Tedesco FJ. Ileo-cecal valve prolapse: confusion with carcinoma of the cecum. Am J Gastroenterol 1978;70:404-6.