226

The Korean Journal of Pathology2008; 42: 226-8

We report here on a case of fibrovascular polyp arising in the hypopharynx of a 62-year-oldman. Laryngomicroscopic surgery with laser ablation was performed to excise the mass.Histopathologically, the surface of the polyp was covered with mature squamous epithelium.The polyp showed a characteristic lobular proliferation of mature adipose tissue that wasseparated by myxoid or collagenous connective tissue. Some scattered skeletal muscle bun-dles were seen in the central portions of the polyp and these bundles were surrounded by aconcentric proliferation of the spindle cells; this was reminiscent of Pacinian corpuscles. Regard-ing their location and the intermingled pattern of proliferating tissues, it is more plausible thatthe skeletal muscle is a hamartomatous component rather than entrapped, preexisting tissue.

Key Words : Polyp; Hypopharynx; Adipose tissue; Skeletal muscle

Sunhee Chang∙∙Sang Hwa ShimJi Eun Kwak∙∙Mee JooHanseong Kim∙∙Bum Jo Jung1

Joong Wook Shin1∙∙See Young Park1

Kyung-Ja Cho2∙∙Je G. Chi

226

Fibrovascular Polyp of the Hypopharynx

- A Case Report -

226 226

Corresponding AuthorSunhee Chang, M.D.Department of Pathology, InJe University Ilsan PaikHospital, 2240 Daewha-dong, Ilsan-gu, Goyang 411-706, KoreaTel: 031-910-7138Fax: 031-910-7139E-mail: changsh@ilsanpaik.ac.kr

Departments of Pathology and 1Otorhinolaryngology, InJe UniversityIlsan Paik Hospital, Goyang; 2Department of Pathology, University ofUlsan College of Medicine, Asan Medical Center, Seoul, Korea

Received : November 28, 2007Accepted : May 6, 2008

Fibrovascular polyps of the upper aerodigestive tract are rarebenign tumors that usually arise at the level of the cricopharyn-geus.1 They histologically consist of fibrous tissue, adipose tis-sue, and vascular structures, which are covered with squamousepithelium.2 They can grow to extreme sizes over several years,resulting in their common designation as ‘‘giant fibrovascularpolyps’’. These patients present with nonspecific symptoms thatare associated with esophageal and respiratory obstruction thatcan often progress to potentially catastrophic airway complica-tions. Timely diagnosis and management are essential to pre-vent the morbidity and mortality associated with these lesions.We report here on a case of 62-year-old man with an asymp-tomatic fibrovascular polyp that arose in the hypopharynx.

CASE REPORT

A 62-year-old man was admitted to our hospital with a hy-

popharyngeal mass that had been incidentally found on a healthcheck-up. The flexible fiberoptic laryngoscopy and physicalexamination revealed a polyp arising from the right pyriformsinus. A computed tomography scan of the neck showed anintraluminal, protruding, well defined mass in the pyriformsinus. Laryngomicroscopy surgery with laser ablation was per-formed and the mass was excised.

Pathologic findings

The resected mass was fragmented and the aggregate mea-sured 3×2×1.8 cm. Its outer surface was glistening and tan-pink. The cut surface showed various sized lobules of adiposetissue admixed with fibrous tissue (Fig. 1). Histologically, thesurface of the polyp was covered with mature squamous epithe-lium. The polyp showed a characteristic lobular proliferation ofmature adipose tissue that was separated by myxoid or collage-nous connective tissue (Fig. 2). Some scattered skeletal muscle

Fibrovascular Polyp of Hypopharynx 227

bundles were seen in the central portions of the polyp. Thesebundles were surrounded by a concentric proliferation of thespindle cells, which was reminiscent of Pacinian corpuscles, withperipheral lymphoplasmacytic cuffing being noted as well (Fig.3A). The skeletal muscle component had preserved cross stria-tions, and these were highlighted by immunostaining for desmin(Fig. 3B). A proliferation of thick-walled blood vessels and cap-illaries was also present. The areas between or within the lobulesshowed a diffuse proliferation of elongated spindle stromal cellswith mild nuclear atypia, and these cells were positive for vimentinand negative for S100 protein or HMB45 on immunostaining.

DISCUSSION

Fibrovascular polyps are expansions of the lamina propria,and they are composed of a mixture of loose, collagenized, highly

vascularized tissue and adipose tissue in various proportions.3

Depending on the predominant histologic components, theselesions have been called lipomas, fibromas, fibrolipomas, fibro-myxomas, fibroepithelial polyps or myxoid neurofibromas.3-5

To avoid potential misdiagnoses, the World Health Organiza-tion’s international histologic classification of tumors recom-mends that the term fibrovascular polyp be used to classify allthe lesions with the aforementioned characteristics.6 Caceres et al.analyzed the world literature and reported on 110 cases of polypsoriginating in the esophagus and hypopharynx under the termsthat included fibrovascular polyp, hamartoma, lipoma, fibrolipo-ma and fibroma.7 Sixteen percent of these polyps were found tooriginate in the hypopharynx. We were able to find 7 cases ofesophageal fibrovascular polyp and one case of hypopharyngealfibrovascular polyp in the Korean literature.8-15 Among thesereports, Hwang et al. described the detailed pathological find-ings of typical fibrovascular polyp of the esophagus in a patient

Fig. 1. The cut surface shows soft, yellow tan, and solid appear-ance.

Fig. 3. (A) Small and short bundles of skeletal muscle are surrounded by capsules composed of concentric layers of elongated cells andlymphoplasma cells. (B) The skeletal muscle tissue is positive for desmin on immunohistochemical staining and shows cross-striations (inset).

A B

Fig. 2. The polyp is composed of mature adipose tissue, collage-nous and myxoid tissue, and lymphoid cells.

228 Sunhee Chang∙Sang Hwa Shim∙Ji Eun Kwak, et al.

with a history of dysphagia.15

According to the histologic description of the previous reports,the constituents of fibrovascular polyps were adipose tissue, stro-mal cells, variable sized vessels and lymphoid tissue. Aside fromthose common components, a skeletal muscle component wasfound in the center of the lesion in our present case. Regarding theskeletal muscle component’s location and its intermingled pat-tern with the other proliferating tissues, it is more plausible thatthe skeletal muscle should be considered as the hamartomatouscomponent rather than as entrapped preexisting tissue. Therehave been several previous reports of oral and/or pharyngeal rhab-domyomas, which are benign and highly differentiated tumorsof striated muscle. However, Patterson et al. reported one case ofhamartoma that showed aberrant skeletal muscle accompaniedwith proliferations of fibrous tissue and fat in the hypopharynx.16

The pathogenesis of this lesion is controversial. It is postulat-ed that the fibrovascular polyp originates as a small polypoidlesion in the loose submucosal tissue of the cervical esophagusand that its growth and elongation are secondary to peristalsis.Others report that the near-normal stromal tissue compositionsuggests that these lesions may be either hamartomas of thelamina propria or a type of inflammatory polyp.3,8,15 The possi-bility of hamartomatous proliferation can be supported by thepresent case with its skeletal muscle component.

The discovery of fibrovascular polyp is usually preceded by ahistory of progressive dysphagia, regurgitation of the mass or thesensation of having a persistent lump in the throat. By contrast,the patient in our present case had not complained of symptomsrelated with esophageal or respiratory obstruction. Seshul et al.also reported on a case that was incidentally found during a cervi-cal ultrasound evaluation.17 These findings would imply that eventhose patients with a history of symptoms related to the fibrovas-cular polyp must have gone through an asymptomatic periodbefore the mass attained a size sufficient to merit clinical attention.

Fibrovascular polyps of the esophagus and hypopharynx shouldbe recognized as uniformly benign lesions that are cured by exci-sion. Malignant transformation of this lesion is extremely rare.Three cases of fibrovascular polyp with squamous cell carcino-ma of the overlying mucosa and one case with liposarcoma havebeen reported in the literature.8,15,18

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