You are in: eMedicine Specialties > General Surgery > Colorectal Perianal CystsArticle Last Updated: Jun 12, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Ruben Peralta, MD, FACS, Professor of Surgery, Anesthesia and Emergency Medicine, Senior Medical Advisor, Board of Directors, Program Chief of Trauma, Emergency and Critical Care, Consulting Staff, Professor Juan Bosch Trauma Hospital, Dominican Republic Ruben Peralta is a member of the following medical societies: American College of Surgeons, American Medical Association, Association for Academic Surgery, Eastern Association for the Surgery of Trauma, Massachusetts Medical Society, Society of Critical Care Medicine, and Society of Laparoendoscopic Surgeons Coauthor(s): Sarah Guzofski, MD, Staff Physician, Department of Psychiatry, University of Massachusetts Medical School; Clifford Y Ko, MD, MS, Assistant Professor, Department of Surgery, University of California at Los Angeles School of Medicine Editors: Marc D Basson, MD, PhD, MBA, Professor, Department of Surgery, Wayne State University School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Amy L Friedman, MD, Professor of Surgery, Director of Transplantation, State University of New York Upstate Medical University College of Medicine, Syracuse; Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy; John Geibel, MD, DSc, MA, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital Author and Editor Disclosure Synonyms and related keywords: epidermoid cysts, sebaceous cysts, epithelial cysts, epidermal cysts, dermoid cysts, inclusion dermoid cysts, sequestration cysts, anal duct cysts, anal gland cysts, sacrococcygeal teratomas INTRODUCTIONSection 2 of 12
  Cysts may occur anywhere in the body, including the skin of the anal region. These cysts include epidermoid cysts, which also are known as sebaceous, epithelial, or epidermal cysts, and dermoid cysts, also called inclusion dermoid or sequestration cysts. However, other cysts, found only in the perianal region, also exist, namely, anal duct or anal gland cysts and sacrococcygeal teratomas. Before reviewing the anatomy of the region, defining specific terminology is helpful. The definition of the perianal region has been quite variable in other sources. For the purposes of this article, the perianal region is defined as the region of the anus, both internal and external. A cyst is defined as an abnormal sac with a membranous lining, containing gas, fluid, or semisolid material. Most perianal cysts are 1 of 4 types, termed (1) epidermoid, (2) dermoid, (3) anal duct/gland, and (4) sacrococcygeal teratoma. Although cysts differ in terms of epidemiology, etiology, and outcome, the diagnostic evaluation of all types is similar and must include ruling out malignancy. Although this is an unusual presentation, rare cases of cancer discovered in cysts have been reported. For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education articles, Anal Abscess, Rectal Pain, Rectal Bleeding, and Constipation in Adults. Frequency
Etiology
ClinicalPatients commonly complain of perianal swelling, with pain or soreness if inflamed. Occasional painless rectal bleeding may be present. If the mass is large enough, patients may complain of constipation due to rectal obstruction or recurrent urinary tract infections due to obstruction of the bladder neck. If a sacrococcygeal teratoma has directly invaded the nerve roots of the cauda equina or metastasized to the spinal cord, the patient may complain of neurologic symptoms such as lower-extremity numbness or weakness; however, this is very rare. Upon physical examination, perianal cysts present similarly, as follows:
The differential diagnosis of perianal cysts should include the following: hemorrhoids; fistulas; abscess; pilonidal cyst/sinus; hidradenitis; trauma; perianal dermatoses, including anal duct/gland cysts; benign teratomas; epidermoid and dermoid cysts; and anal/skin cancer, including malignant teratomas and teratomas with malignant transformation. INDICATIONSSection 3 of 12
Complete surgical excision is the treatment of choice for perianal cysts (see Surgical therapy). RELEVANT ANATOMYSection 4 of 12
Lesions of the anus should be described as right or left lesions or anterior or posterior lesions rather than as a position on a clock face, which depends on whether the patient is in a prone or supine position. Perianal skin contains both apocrine sweat glands (ie, sweat glands in association with hair follicles that secrete a viscous odorless sweat) and eccrine sweat glands (ie, a coiled sweat gland, different from apocrine glands); however, many of the apocrine glands, although present, remain functionless. A variable number of sebaceous (ie, oil-secreting) glands are present in the perianal region, either opening into a hair follicle or as individual free sebaceous glands at the anal verge. Inflammation of any of these glandular units may lead to the development of an epidermoid cyst. The anal verge is the transitional zone between the perianal skin and the moist, hairless, modified skin of the anal canal. The anal canal is the portion of the distal segment of the intestinal tract that lies between the termination of the rectal mucosa superiorly and the beginning of the perianal skin. This skin can be differentiated from the distal anal canal by the presence of the epidermal appendages mentioned previously (ie, sweat glands and hair follicles). The anal canal has an average of 6-12 anal ducts, which open into anal crypts (also known as anal sinuses or Morgagni sinuses). Most of these ducts have orifices in the posterior portion of the anal canal. Communicating with the ducts are straight or spiral, slender, tubular structures called the anal glands. These glands, imbedded in the mucous membrane of the anus, secrete a viscous sweat, lubricating the anal canal. CONTRAINDICATIONSSection 5 of 12
As for any procedure, surgical treatment is contraindicated if the patient is a poor operative candidate. This includes careful risk-benefit consideration for individuals with severe pulmonary and/or cardiac disease. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
Diagnostic Procedures
Histologic Findings
StagingSacrococcygeal teratomas in adults most commonly are benign, also called a mature teratoma. Rare cases have been reported of adults with malignant teratomas, which contain frankly malignant tissue of germ cell origin, such as germinoma (eg, seminoma or dysgerminoma) and choriocarcinoma, in addition to mature and/or embryonic tissues. Tumors containing malignant nongerm cell elements have been termed teratoma with malignant transformation, which includes adenocarcinoma or squamous cell carcinoma found in mature teratomas of adults. Patients with either a malignant teratoma or a benign teratoma with malignant transformation have a considerable increase in mortality, dying from the disease within 2 months to 2 years. This is in comparison to patients with benign disease, who are alive without disease as long as 4 years after treatment. The majority of teratomas in infancy and childhood also are benign; however, in this population, a tendency exists towards increasing malignant potential with increasing age. Therefore, surgical excision is performed almost uniformly. TREATMENTSection 7 of 12
Medical therapyNo particular medical treatment is available for perianal cysts. Surgical therapyComplete surgical excision is the treatment of choice. The majority of sacrococcygeal teratomas can be removed through a sacral approach; however, if the tumor extends greatly into the pelvis and retroperitoneum, an additional abdominal incision may be necessary to completely excise the tumor. It is recommended that the coccyx also be removed in sacrococcygeal teratomas because failure to remove it has been associated with a high risk of recurrence. For malignant teratomas, surgical excision alone is inadequate, and patients should receive additional treatment with chemotherapy and/or radiotherapy. For histologically benign teratomas, adequate surgical excision is virtually curative. For the 3 other cyst types, a transrectal approach may be used. If an abscess is suggested, incision and drainage are recommended with an appropriate course of antibiotics. The fetus with sacrococcygeal teratoma has an increased risk of perinatal complications, for example from tumor rupture or dystocia. In some cases, in utero interventions, such as tumor de-bulking and cyst aspiration, may be considered. Preoperative detailsA colorectal surgeon may be consulted to aid in the excision of the cyst. The patient also may be referred to a dermatologist if anal skin cancer or perianal dermatoses are suggested. Postoperative detailsNo particular diet affects the natural history of these cysts. However, patients should be placed on a high-fiber diet postoperatively to prevent wound dehiscence from straining. Patients with perianal cysts are not limited in their activities. Postoperatively, patients may find sitz baths helpful for decreasing their discomfort. Postoperative chemotherapy/radiotherapy may be necessary in patients with malignant teratomas or teratomas with malignant transformation. Because sacrococcygeal teratomas are rare, no standard recommendation exists for the use of chemotherapy or radiation. Follow-upOnly in rare cases is inpatient care necessary for the management of perianal cysts. For sacrococcygeal teratomas, however, postoperative outpatient follow-up is crucial. If complete resection is accomplished, a full physical examination should be performed periodically, with emphasis on assessment of the perineal and presacral area by rectal examination. CT scan or MRI may be useful if a recurrence is suggested. For the other 3 types of cysts, follow-up with a physician for assessment of wound healing and fecal incontinence is recommended. Chemotherapy and/or radiotherapy may be necessary for patients diagnosed with malignancy. Education for patients with malignancy involves a treatment plan and any necessary referrals, such as with an oncologist and colorectal surgeon. The patient should be instructed in proper hygiene to maintain a clean and dry perianal area, especially during wound healing. COMPLICATIONSSection 8 of 12
Bleeding and infection are potential complications of any surgical procedure. Profuse bleeding rarely is a major complication because no major blood vessels are present in the perianal region. Good hygiene during wound healing can reduce the risk of infection. Fistula formation is a rare complication; however, the risk may be slightly increased in dermoid cysts because they may contain hair projecting from a sinus tract. Fecal incontinence also is a rare complication; the risk depends on the position of the cyst and the age, sex, and past medical history of the patient. Neurogenic bladder is a potential complication of both sacrococcygeal teratoma and its surgical treatment. OUTCOME AND PROGNOSISSection 9 of 12
For patients with malignant teratomas or teratomas with malignant transformation, the prognosis is less favorable. It is even worse if neurologic involvement is present. However, if the diagnosis is a benign teratoma, adequate surgical resection is virtually curative. For the other 3 types of cysts, prognosis is excellent. FUTURE AND CONTROVERSIESSection 10 of 12
Of special concern is the association of genetic presacral teratomas with anal and urinary anomalies. The Currarino triad is an autosomal-dominant condition that consists of anorectal stenosis, a sacral bony anomaly in which the sacrum has a crescent shape, and a presacral mass. This mass can be a meningocele, a teratoma, a dermoid, a lipoma, an enteric or duplication cyst, a hamartoma, or a combination of these and rarely is malignant. The anus may appear normal; however, due to the stenosis, it may be impossible to insert a finger. Often, intractable constipation is present. Use caution when excising the presacral mass because communication exists with the dura mater and cerebrospinal fluid. ACKNOWLEDGMENTSSection 11 of 12
The authors and editors of eMedicine gratefully acknowledge the contributions of previous coauthor, Kim Takahashi, MD, to the development and writing of this article. REFERENCESSection 12 of 12
Article Last Updated: Jun 12, 2006 |
