Surg Today (2008) 38:1133–1136DOI 10.1007/s00595-007-3754-7

Reprint requests to: B. KumarReceived: March 6, 2007 / Accepted: December 5, 2007

Mature Solid Teratoma of the Rectum: Report of a Case

BIPIN KUMAR1, MANOJ KUMAR

2, RAJEEV SEN1, and NITISH ANCHAL

2

Departments of 1 Pathology and 2 Surgery, B.P. Koirala Institute of Health Sciences, Ghopa, Dharan, Nepal

AbstractA case of an unusual occurrence of mature solid tera-toma of the rectum is reported with a review of the lit-erature. A 30-year-old woman presented with bleeding per anum without any alteration in her bowel habits. Sigmoidoscopy revealed a pedunculated polypoidal mass arising from the posterior wall of the rectum. A polypectomy specimen on microscopy showed the com-ponents of all the three germ layers. This may be the largest polypoidal type of rectal teratoma reported in the English literature to date. A review of the literature indicated only 50 previously reported cases, with all except one being female. The common presentations include prolapse and bleeding per anum.

Key words Teratoma · Rectum · Germ layer

Introduction

Teratoma is a tumor composed of parenchymal cell types representative of more than one germ layer, usually all three.1 Extragonadal teratomas arise from totipotent cells in sequestered primitive cell rests. Only a few cases of rectal teratoma have previously been reported in the English literature.2–11

Case Report

A 30-year-old woman presented with the chief com-plaint of bleeding per anum for 6 months without an alteration of bowel habits. A rectal examination did not reveal any abnormality except for blood staining. Sig-

moidoscopy showed a single pedunculated polypoidal mass arising from the mucosa of the posterior wall of the rectum 10 cm above the anal verge. Her hemoglobin was 6.5 g%. A peripheral smear showed microcytic hypochromic anemia. All other abdominal viscera and pelvic organs were normal on radioimaging inves-tigations. Routine biochemical tests were all within normal limits. With the clinical diagnosis of solitary adenomatous rectal polyp, a polypectomy was done and the specimen was sent for a histopathological examination.

Pathological Findings

The polypectomy specimen measured 6 × 3 × 3 cm including a 2.5-cm long stalk. The outer surface was smooth, glistening to wrinkled skin tone with a few hairs, and a few small blood vessels at the base of the peduncle (Fig. 1). The cut surface was solid but varie-gated and showed adipose tissue, and chondroid and bony hard tissues (Fig. 2).

A microscopic examination revealed a polyp covered with keratinizing stratifi ed squamous epithelium except at the base of peduncle, which showed rectal mucosa. Sweat glands, sebaceous glands, and hair follicles were seen under the epithelial surface of the polyp (Fig. 3).

The central portion was composed of mature adipose tissue, cartilage, bone with bone marrow (Fig. 4); neural tissue and blood vessels (Fig. 5); and lobules of breast (Fig. 6) and ovarian stroma (Fig. 7).

Discussion

Teratoma is a germ cell tumor classifi ed into mature and immature types. Teratomas may be solid or cystic. Extragonadal teratoma may involve the retroperito-neum, mediastinum, and the sacrococcygeal region. Teratoma of the gastrointestinal tract is rare and few

1134 B. Kumar et al.: Teratoma of the Rectum

Fig. 1. Outer surface. A smooth, glistening to wrinkled skin tone with a few hairs is apparent

Fig. 2. Cut surface showing adipose tissue, with chondroid and bony hard tissue

Fig. 3. Microscopic examination revealing a keratinized strat-ifi ed squamous epithelium with skin adnexal structures (H&E, ×10)

Fig. 4. Microscopic examination revealing adipose tissue (single arrow), cartilage (double arrows), and bone (triple arrows) (H&E, ×10)

cases arising from the rectum have so far been reported.2–10 It is thought that primary rectal teratoma is also of germ cell origin from an aberrant germ cell remnant in the digestive tract. During embryogenesis, germ cells migrate on a path from the endoderm of the yolk sac to the gonads via the dorsal mesentery of the hindgut, and the remainder of the totipotent cells may become sequestered along this path.8,11 The adrenal gland, urinary tract, and rectum are adjoining struc-tures. In view of the above-mentioned embryogenic mechanism, those germ cells have a chance to enter the rectum aberrantly and thus create a rectal teratoma.8

In an extensive Medline search with the key words “Teratoma”, “Rectum,” and “Germ Layer”, we found

B. Kumar et al.: Teratoma of the Rectum 1135

case of a submucosal dermoid cyst of the rectum as reported in literature.7,8 In only two cases, the site of origin of the tumor was in the lateral wall.2,7 In almost all cases the tumor was solitary except in two patients having two or more tumors.7 Most of the tumors were polypoidal in shape except in four cases of submucosal dermoid cyst.7,8 Most of the polypoidal tumors including the present case were pedunculated.3,10 One tumor was walnut-sized.5 The largest size of the reported polypoi-dal tumor in maximum dimension was 4.2 cm, in com-parison to 6 cm including a 2.5-cm long peduncle in the present case.10 The smallest size of the submucosal dermoid cyst was 1.2 cm, while the largest occupied almost the entire pelvic cavity.7,8 Most of these tumors were solid; however, a few purely cystic tumors have also been reported, of which in one case the cyst was entirely covered with a fi brous and fi rm capsule.8 The maximum distance of the tumor from the anal verge was 15 cm.10 In two cases the tumors involved the anal canal in addition to the rectum.6,9 Only one case of immature teratoma has been reported.4 In most of the cases, the tumor histologically consists of derivatives of all three germ layers; however, a few cases of dermoid cyst of the rectum have also been reported.

Rectal bleeding due to polypoidal lesions in a female patient may thus suggest a rectal teratoma as a possible cause. The excision of the lesion is curative as, by and large, these tumors are usually benign.

References

1. Kumar V, Abbas Abul K, Fausto N. Robbins and Cotran patho-logic basis of disease. 7th ed. Indian edition Reprint; 2005. p. 271.

2. Aldrige M, Boylston AW, Sim AJW. Dermoid cyst of the rectum. Dis Colon Rectum 1983;26:333–4.

Fig. 5. Histological section showing neural tissue (single arrow) and blood vessels (double arrows) (H&E, ×10)

Fig. 6. Histological section showing breast lobules (H&E, ×10)

Fig. 7. Histological section showing ovarian stroma (H&E, ×10)

only 51 cases including the present case to have been reported since 1865.8–10 Rectal teratoma has been reported in a male patient only once,7 all the other patients being women.7 Germ cells may more easily enter the rectum aberrantly in women because of its close proximity to the ovaries. A wide age range has been described, ranging from a congenital anorectal teratoma to 80 years.

Many of the patients presented with a prolapse of the tumor or hair, and many had a bloody stool.3,7 One case of postmenopausal bleeding was noted to have a rectal mass during a clinical examination.3 In one pregnant woman, the tumor was accidentally found during a checkup after a miscarriage.8 In another case, the pre-senting complaint was constipation.10

The most common site of the tumor growth was the anterior wall of the rectum whereas in the present case the tumor arose from the posterior wall, such as in a

1136 B. Kumar et al.: Teratoma of the Rectum

3. Green JB, Timmcke AE, Mitchell WT Jr. Endoscopic resection of primary rectal teratoma. Am J Surg 1993;59:270–2.

4. Govender D, Hadley GP, Bairstow S. Immature teratoma of the rectum presenting with prolapse per anum. Pediatr Surg Int 1995;10:194–5.

5. Tabuchi Y, Tsunemi K, Matsuda T. Variant type of teratoma appearing as a primary solid dermoid tumor in the rectum: report of a case. Surg Today 1995;25:68–71.

6. Jona JZ. Congenital anorectal teratoma: report of a case. J Pediatr Surg 1996;31:709–10.

7. Takao Y, Shimamoto C, Hazama K, Itakura H, Sasaki S, Umegaki E, et al. Primary rectal teratoma: EUS features and review of the literature. Gastrointest Endosc 2000; 51:353–5.

8. Sakurai Y, Uraguchi T, Imazu H, Hasegawa S, Matsubara T, Ochiai M, et al. Sub mucosal dermoid cyst of the rectum: report of a case. Surg Today 2000; 30:95–8.

9. Chwalinski M, Nowacki MP, Nasierowska-Guttmejer A. Anorec-tal teratoma in an adult woman. Int J colorectal Dis 2001;16:398–401.

10. Park KS, Kang M, Kim YJ, Kim CH, Yoon HK. Mature teratoma of the rectum — a case report. Kor J Pathol 2001;35:83–5.

11. Schuetz MJ 3rd, Elsheikh TM. Dermoid cyst (mature cystic teratoma) of the caecum. Arch Pathol Lab Med 2002;126:97–9.