Endorectal Sonography in the Evaluation of Rectal and Perirectal Disease

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503 I. Pictorial Essay I Endorectal Sonography in the Evaluation of Rectal and Perirectal Disease Edward W. St. Ville,1 S. Zafan H. Jafri,1 Beatrice L. Madrazo,1 Duane G. Mezwa,1 Robert L.

1 503 I. Pictorial Essay I Endorectal Sonography in the Evaluation of Rectal and Perirectal Disease Edward W. St. Ville,1 S. Zafan H. Jafri,1 Beatrice L. Madrazo,1 Duane G. Mezwa,1 Robert L. Bree,2 and Barbara F. Rosenberg3 Endorectal sonography initially was developed for evaluation of the prostate and now has been adapted for evaluation of rectal and perirectal disease. We used endorectal sonography to evaluate a spectrum of diseases, including primary and recurrent rectal carcinoma, metastases, villous adenoma, leiomyosarcoma, endometnosis, sacrococcygeal teratoma, chordoma, retroperitoneal cystic hamartoma, pelvic lipomatosis, diverticulitis, and perirectal abscess. The technique has been useful in localization of penrectal abscesses and in sonographically guided biopsy of perirectal masses. Knowledge of normal sonographic anatomy of the rectum is essential in the evaluation of rectal and perirectal disease. In this essay, we describe the technique of endorectal sonography and illustrate the sonographic findings in a variety of diseases. The rectum and peninectal space are the sites of numerous diseases, both benign and malignant. Because of the anatomic detail provided by endonectal sonography, it is useful for the evaluation of the direction of spread of rectal disease, depth of tumor penetration, and assessment of invasion of adjacent viscera [1, 2]. The technique provides accurate definition of the layers of the rectal wall and peninectal soft Fig. 1.-Sonogram and drawing show five layers of normal rectum: (1) interface between balloon and mucosa, (2) deep mucosa and muscularis mucosa, (3) interface between submucosa and musculans propria, (4) musculans propria, and (5) interface between musculans propna and penrectal fat. Received January 24, 1991; accepted after revision April 17, Presented at the annual meeting of the American Roentgen Ray Society, Washington, DC, May Department of Diagnostic Radiology, William Beaumont Hospital, 3601 W. Thirteen Mile Rd., Royal Oak, Ml Address reprint requests to S. Z. H. Jafri. 2 of Diagnostic Radiology, Veterans Administration Hospital, 2215 Fuller Rd., Ann Arbor, Ml of Surgical Pathology, William Beaumont Hospital, Royal Oak, MI AJR 157: , september X/91/ American Roentgen Ray Society

504 ST. VILLE ET AL. AJR:157, September 1991 Fig. 2.-Primary rectal carcinoma confined to rec- Fig. 3.-Primary rectal carcinoma with local invasion. tal wall.

propria (arrows). (arrows). B, Sonogram obtained at a higher level reveals mass, which appears to disrupt muscularis propria (arrows) and invade penrectal fat planes. Fig. 4.

A, Endorectal sonogram shows a well-defined mass of mixed echogenicity in posterior wall of rectum that disrupts muscularis layer and invades perlrectal fat (arrows).

B, CT scan at same level shows a soft-tissue mass in posterior rectal wall with extension into perirectal fat (arrow).

Sonogram obtained after abdominoperineal resection shows diffuse thickening of rectal wall and disruption of muscularis propria (arrowheads).

2 504 ST. VILLE ET AL. AJR:157, September 1991 Fig. 2.-Primary rectal carcinoma confined to rec- Fig. 3.-Primary rectal carcinoma with local invasion. tal wall. Endorectal sonogram shows a well-defined A, Sonogram shows soft-tissue mass with muscularis propria in left anterolateral wall of rectum hypoechoic lesion confined to muscularis propria (arrows). (arrows). B, Sonogram obtained at a higher level reveals mass, which appears to disrupt muscularis propria (arrows) and invade penrectal fat planes. Fig. 4.-Primary rectal carcinoma with local invasion. A, Endorectal sonogram shows a well-defined mass of mixed echogenicity in posterior wall of rectum that disrupts muscularis layer and invades perlrectal fat (arrows). A well-defined hypoechoic area (arrowhead) represents extension of tumor to a perirectal lymph node. B, CT scan at same level shows a soft-tissue mass in posterior rectal wall with extension into perirectal fat (arrow). Microscopic section revealed invasive mucin-producing adenocarcinoma of rectum with extension into perirectal fat. Fig. 5.-Recurrent rectal carcinoma. Sonogram obtained after abdominoperineal resection shows diffuse thickening of rectal wall and disruption of muscularis propria (arrowheads). Enlarged perirectal lymph nodes also were identified (open arrow). Surgical suture is present in anterior rectal wall (solid arrow). Biopsy revealed recurrent rectal carcinoma. Fig. 6.-Villous adenoma. A, Endorectal sonogram shows a well-defined area of mixed echogenicity contained within muscularis propria layer in anterior rectal wall (arrows). B, Air-contrast barium enema shows marked mucosal irregularity in anterior rectal wall (arrow). Microscopic section of resected specimen showed characteristic frondlike appearance of villous adenoma.

Microscopic section revealed a discrete area of malignant spindle cell proliferation corresponding to a 1.5-cm Ieiomyosarcoma found in gross pathologic specimen.

A, Sonogram shows large, pooriy defined hypoechoic mass disrupting perirectal soft-tissue planes anteriorly between prostate (P) and rectum (arrows).

Diagnosis of carcinoma was confirmed by results of transrectal biopsy. Fig. 9.-Malignant melanoma.

3 Fig. 7.-Leiomyosarcoma. Endorectal sonogram obtained at level of palpable rectal mass in a patient with chronic active ulcerative colitis shows a uniform hypoechoic lesion limited by muscularis propria layer (arrows). Microscopic section revealed a discrete area of malignant spindle cell proliferation corresponding to a 1.5-cm Ieiomyosarcoma found in gross pathologic specimen. This neoplasm was confined to muscularis propna. Overlying submucosa and mucosa are obliterated as a result of chronic active ulcerative colitis. Fig. 8.-carcinoma of prostate. A, Sonogram shows large, pooriy defined hypoechoic mass disrupting perirectal soft-tissue planes anteriorly between prostate (P) and rectum (arrows). B, CT scan at same level shows a soft-tissue mass posteriorly between prostate and perirectal soft-tissue planes with extension into anterior rectal wall (arrowheads). Diagnosis of carcinoma was confirmed by results of transrectal biopsy. Fig. 9.-Malignant melanoma. A, Endorectal sonogram shows a hypoechoic mass in left seminal vesicle (arrow) in a patient with malignant melanoma. B, Sonogram obtained at a lower level shows a well-defined hypoechoic metastasis in left lobe of prostate that disrupts and Invades anterior rectal wall (arrow). Fig. 10.-Endometriosis. Sonogram shows a well-demarcated area (arrows) interposed between muscularis propria and mucosa. Lesion is confined by and does not extend beyond muscularis propria. Histologic examination showed a focus of endometriosis, which was delimited by muscularis propria. Fig. 11.-Lipomatosis. A, Sonogram shows pelvic lipomatosis with perlrectal deposition of fat causing anterior displacement of left seminal vesicle (small arrow). Note asymmetry of echo texture of perirectal tissue between seminal vesicle and rectum, with decreased echogenicity on left (larg. arrow) simulating a mass. B, Ti-weighted MR image of pelvis shows a uniform circumferential ring of increased signal Intensity In perirectal soft tissues consistent with lipomatosis. Note more anterior location of left seminal vesicle relative to right (arrow). No masses were Identified. A B

506 ST. VILLE ET AL. AJR:157, September 1991 Fig. 12.-Chordoma. A, Endorectal sonogram shows a complex mass posteriorly that lies outside rectal wall.

B, CT scan at same level shows soft-tissue mass posterior to rectum that contains tiny calcifications and appears to extend into coccyx (ar. row). Fig. 13.-Diverticulitis.

B, CT scan of pelvis confirms edema and thickening of wall of rectosigmoid colon (arrows). A B Fig. 14.-Perirectal abscess.

4 506 ST. VILLE ET AL. AJR:157, September 1991 Fig. 12.-Chordoma. A, Endorectal sonogram shows a complex mass posteriorly that lies outside rectal wall. Mass is mostiy hypoechoic and poorly defined and contains several bright reflectors (arrow) caused by tiny calcifications. B, CT scan at same level shows soft-tissue mass posterior to rectum that contains tiny calcifications and appears to extend into coccyx (ar. row). Fig. 13.-Diverticulitis. A, Sonogram shows hypoechoic area in anterior rectal wall outside muscularis propria. Fluid extends into penrectal soft tissues (arrows). B, CT scan of pelvis confirms edema and thickening of wall of rectosigmoid colon (arrows). A B Fig. 14.-Perirectal abscess. A, CT scan in a patient with inflammatory bowel disease shows perirectal abscess anterior to rectum (arrow) that could not be found during surgery. B, Endorectal sonogram obtained after surgery shows a poorly defined hypoechoic area anterior to rectum (arrows). C, Under sonographic guidance, a guidewire (arrows) was inserted and secured to skin. Surgery was repeated, and guidewire was used successfully to locate abscess cavity.

AJR:157, September 1991 SONOGRAPHY IN RECTAL DISEASE 507 Fig. 15.-Sacrococcygeal teratoma. Endorectal Fig. 16.-Retroperitoneal cystic hamartoma (tailgut cyst).

wall. B, CT scan at level of tailgut cyst (arrow) correlates with endorectal sonogram, revealing a perirectal soft-tissue mass (M) in presacral space that narrows rectal lumen. tissues (Fig. 1).

In this essay, we describe the technique of endonectal sonognaphy and illustrate the sonognaphic findings in a variety of diseases.

5 AJR:157, September 1991 SONOGRAPHY IN RECTAL DISEASE 507 Fig. 15.-Sacrococcygeal teratoma. Endorectal Fig. 16.-Retroperitoneal cystic hamartoma (tailgut cyst). sonogram shows a well-defined hypoechoic mass, A, Sonogram shows a homogeneous well-circumscribed hypoechoic mass (M) compressing with acoustic enhancement outside posterior rectal rectum (arrow). wall. B, CT scan at level of tailgut cyst (arrow) correlates with endorectal sonogram, revealing a perirectal soft-tissue mass (M) in presacral space that narrows rectal lumen. tissues (Fig. 1). Anatomic changes caused by soft-tissue masses, cysts, calcification, and fluid collections can be detected. In this essay, we describe the technique of endonectal sonognaphy and illustrate the sonognaphic findings in a variety of diseases. Pathologic verification of sonognaphic findings was available in all cases. Technique An axial, transversely oriented radial scanner (model 1850, BnUel & Kjaen, Copenhagen, Denmark) is used most commonly. The total length of the rigid probe with the transducer is 24 cm. The transducer rotates at a rate of two to three cycles pen second. Scanning radial to the long axis of the rectal probe provides a 360#{176} display of the rectum and surrounding tissues. The transducer, covered by a disposable latex sheath and lubricated with a scanning gel, is introduced into the rectum. A minimum luminal diameter of 25 mm is necessary to insert the probe. The sheath is filled with 60 ml of degassed water to provide an acoustic window. Images routinely are obtained at 1 -cm intervals from approximately cm above the anus, which is the usual maximal depth of insertion. The transducer also can be inserted via a nectoscope to evaluate the rectum. During simultaneous withdrawal of the probe and the rectoscope, the region of interest is scanned in a stepwise fashion. Depending on the extent of the lesion, the examination takes mm. Sonographic Anatomy of the Normal Rectum When a 7-MHz transducer is used, sonograms show five layers in the rectal wall; three are hyperechoic and two are hypoechoic. The first echogenic line corresponds to the interface between the water balloon and the mucosa. The innermost hypoechoic line represents the deep mucosa and musculanis mucosa. The third and most echogenic line is produced by the submucosa. The outer, widen hypoechoic line delineates only the musculans propna. This is of clinical importance because it defines a sonognaphic criterion for determining intramural or extramural invasion. The most peripheral line, the fifth echogenic line, corresponds to the interface between the musculanis propria and peninectal fat. Sonographic Findings in Rectal and Penrectal Disease Endorectal sonognaphy initially was developed for evaluation of carcinoma of the prostate and recently has been adapted for staging of rectal carcinoma and evaluating a spectrum of benign and malignant rectal and penirectal conditions [3]. Rectal carcinoma appears on endonectal sonograms as a low-echogenicity lesion that abruptly interrupts the normal sequence of layers (Figs. 2 and 3). In order to stage the tumor precisely, it is necessary to determine the relationship between the neoplasm and the outer hypoechoic layer (musculanis propnia). When no infiltration has taken place, this layer has a smooth regular course and is separated by the thin echogenic line of submucosa. Disappearance of submucosa may indicate infiltration of the musculanis propnia. This pattern is most difficult to determine. Tumor with minimal extrarectal spread could therefore be understaged also. Extension into the pennectalfat is represented by the interruption of the musculanis propnia by the neoplasm (Fig. 4). In addition, infiltration into the adjoining pelvic organs and penmrectal lymph nodes should be sought. Lymphadenopathy caused by metastases or lymph-node hyperplasia resulting from local sepsis commonly is seen with endorectal sonography. When no lymph nodes are visible in

6 508 ST. VILLE ET AL. AJR:157, September 1991 metastases is low [4]. The enlarged nodes may be hyperechoic and hypoechoic. Hypenechoic lymph nodes are enlarged because of nonspecific inflammatory change. When enlarged lymph nodes are hypoechoic, metastases are most likely, although nonspecific inflammation cannot be excluded. Preoperative assessment of the depth of tumor invasion is important in the treatment of rectal carcinoma, particularly when local excision is being considered. A major value of endonectal sonognaphy is to determine the depth of tumor invasion. The procedure can be used to detect local recurrence after low anterior resection or local excision. Extent of primary on recurrent tumor infiltration is defined more exactly with endorectal sonography than with CT (Fig. 5). The high spatial resolution of endonectal sonography also has proved useful in characterizing the nature and extent of numerous rectal and penirectal disease entities. Endonectal sonognaphy shows villous adenoma (Fig. 6), leiomyosancoma (Fig. 7), metastases (Figs. 8 and 9), endometniosis (Fig. 10), and pelvic lipomatosis (Fig. 11) as nonspecific, solid masses within the rectal wall and perirectal soft tissues. Calcification within a chordoma (Fig. 12) and pennectal fluid collections seen in diverticulitis and peninectal abscess can be demonstrated (Figs. 13 and 14). Sacnococcygeal tenatoma (Fig. 15) and netnopenitoneal cystic hamartoma (Fig. 1 6) are seen as wellcircumscribed masses outside of the rectal wall. Endonectal sonognaphy also has been useful for localization of peninectal abscess and needle biopsy of peninectal masses. REFERENCES 1. Orrom WJ, Wong WD, Rothenberger DA, Jensen LL, Goldberg SM. Endorectal ultrasound in the preoperative staging of rectal tumors: a leaming experience. Dis Colon Rectum 1990;33: Konishi F, Ugajin H, Kanazawa K. Endorectal ultrasonography with a 7.5 MHz linear array scanner for the assessment of invasion of rectal carcinoma. Int J Colorectal Dis 1990;5: Beynon J, Foy DM, Temple LN, Channer JL, Virgee J, Mortenson NJ. The endosonic appearances of normal colon and rectum. Dis Colon Rectum 1986;29: Glaser F, Schlag P, Herfarth C. Endorectal ultrasonography for the assessments of invasion of rectal tumors and lymph node involvement. Br J Surg 1990;77: LIST OF BOOK AND VIDEOTAPE REVIEWS 480 Detection and Treatment of Early Breast Cancer. Fentiman! 490 The Radiologic Clinics of North America. Interventional Radiology of the Biliary Tract. Burhenne HJ, ed. 494 RSNA Today, Vol. 4, No, 5. Casareila WJ, moderator 498 Atlas of Roentgenographic Measurement, 6th ed. Keats TE 516 Magnetic Resonance Imaging of Carcinoma of the Urinary Bladder. Barentsz JO, Debruyne FMJ, Ruijs SHJ 520 Textbook of Uroradiology. Dunnick NR, McCailum RW, SandIer CM 526 MRI of the Musculoskeletal System, 2nd ed. Berquist TH, ed. 532 The Language of Fractures, 2nd ed. Schultz RJ 544 Obstetrics and Gynecology. Berman MC, ed. 584 Neuroradiology Test and Syllabus. Weinberg PE, section ed. 602 Gamuts and Pearls in MRI. Pomeranz SJ 608 A Short Textbook of Clinical Imaging. Sutton D, Young JWR, eds.

Alison Douglass Gillian Lieberman, MD. November. Colon Cancer. Alison Douglass, Harvard Medical School Year III Gillian Lieberman, MD

Alison Douglass Gillian Lieberman, MD. November. Colon Cancer. Alison Douglass, Harvard Medical School Year III Gillian Lieberman, MD November Colon Cancer Alison Douglass, Harvard Medical School Year III Our Patient Mr. K. is a 67 year old man with no prior medical problems other than hemorrhoids which have caused occasional rectal