The endometrium is the inner lining of the uterus (womb); this tissue normally cycles through stages of growth and shedding during the menstrual cycle. Endometriosis occurs when the endometrium is present outside the usual location. Endometriosis may occur in the ovaries, fallopian tubes, vagina, or other parts of the uterus. Rarely, endometriosis may occur in the abdomen and lungs.Endometriosis is common among women of reproductive age. An estimated 11% of women in the United States may have endometriosis. Women without prior pregnancies, women with a family history of endometriosis, and women with abnormal menstrual periods are more likely to have endometriosis.

Hashimoto's disease typically presents with hypothyroidism due to lymphocytic infiltration of the thyroid. Cervical lymphadenopathy has rarely been reported in Hashimoto's disease. We report the unusual association of shifting cervical lymphadenopathy with Hashimoto's disease.