Infectious conditions in the differential diagnosis:
(1) cytomegalovirus (CMV)
(2) Herpes Simplex virus (HSV)
(3) bacterial cellulitis
(4) dermatophyte
(5) Candida
(6) tuberculosis
Malignant conditions in the differential diagnosis:
(1)
recurrent tumor
(2) malignant lymphoma
(3) de novo tumor
Other conditions in the differential diagnosis:
(1) Crohn's disease
(2) ischemic colitis
(3) allergy
A patient may have one or more of the above conditions together with radiation anoproctitis.
Reasons to suspect an alternative diagnosis:
(1)
appearance of lesion outside of radiation field
(2) rapid spread
(3) appearance of lesions new or not typical for radiation injury
(4) immunosuppression
(5) evidence of a disease elsewhere
The diagnosis may require imaging studies, endoscopy, biopsy and microbiology testing.
