Ambiguous Cases

Problem	Response
Fragmented or Distorted	Rebiopsy if worried
Progestin Effect	Withdraw hormones & rebiopsy
Non-Endometrioid Differentiation	If glandular, can use EIN criteria but must rule out specific cancer.
Suspicious for EIN but <1mm	Descriptive Dx & Followup
Suspicious for EIN but >50% VPS	Descriptive Dx & Followup

Diagnosis of lesions suspicious but subdiagnostic for EIN is a contentious topic. This is a small category of cases, in which diagnostic uncertainty may be contributed by a variety of specific and often identifiable causes. An explanation for the lack of a definitive diagnosis should be identified and communicated by the pathologist whenever possible. This will be more relevant in guiding therapy than its indeterminate status per se.

In the case of indeterminate endometria, a descriptive diagnosis with explanatory comments from the pathologist will be helpful in deciding between therapeutic options. For example, the patient who is biopsied while on exogenous progestins may be easier to evaluate after withdrawal of hormones. Controversial histologies such as those obscured by extensive altered cellular differentiation ("metaplasias") should be described clearly. Other specimens may be compromised by sampling errors, or regenerative epithelial changes. All should be clarified by additional studies, including either immediate additional endometrial sampling to detect the presence of diagnostic areas elsewhere in the endometrium, or regular followup with rebiopsy at 6 month intervals to monitor possible progression. Another option would be to attempt a trial of high dose progestins to provide symptomatic relief, followed by a post-withdrawal biopsy.