History and Physical Examination
Patients commonly complain of perianal swelling, [12] 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.
Anal duct/gland cysts
Typically, these present with perianal soreness, tenderness, swelling, and induration. These smooth, subcutaneous, spherical nodules may vary in size from 1 to 2 cm. The anterior anus is involved more commonly than the posterior anus.
Sacrococcygeal teratomas
Commonly, these are large, soft presacral masses felt during the rectal examination during a routine physical examination; they may range from 5 to 25 cm in diameter. Sacrococcygeal teratomas may be asymptomatic upon initial presentation; an infected teratoma may present as an abscess. [13]
Epidermoid cysts
An epidermoid cyst, because it is situated in the dermis, raises the epidermis to produce a firm, elastic, dome-shaped mass that is mobile over deeper structures. It may have a central, keratin-filled punctum and vary in size from a few millimeters to 50 mm. They may be solitary but more commonly are multiple. Over time, these cysts may enlarge and occasionally become inflamed and tender. When epidermoid cysts present in the perianal region, they are superficial and yellowish to white in color. [14]
Dermoid cysts
Typically, these present as subcutaneous, spherical nodules ranging from 6 to 60 mm in diameter, depending on the involved site. Many have a sinus opening from which hair projects. Recurrent infection may be a problem.
