Annual Mammogram and Prostate Cancer Screening Coverage Act of 1998 - Amends the Public Health Service Act and the Employee Retirement Income Security Act of 1974 to require a group health plan, and a health insurance issuer offering group coverage, to provide coverage for annual screening mammograms for participants and beneficiaries 40 years old and older and annual prostate cancer screening testing for male participants and beneficiaries 50 years old and older. Prohibits related eligibility discrimination, monetary incentives to individuals, and penalties or incentives to providers.

Amends the Internal Revenue Code to require a group health plan to provide coverage for annual screening mammograms for participants and beneficiaries 40 years old and older and annual prostate cancer screening testing for male participants and beneficiaries 50 years old and older.

Amends the Public Health Service Act to apply the requirements of this Act to coverage offered in the individual market.

Amends the Health Insurance Portability and Accountability Act of 1996 to mandate coordination of regulations, rulings, and interpretations between the Secretaries of the Treasury, Health and Human Services, and Labor relating to matters over which two or more of the Secretaries have responsibility.