A uterine mass revealed a rare metastasis from lung adenocarcinoma

What happened, in summary

A 65-year-old woman was diagnosed with lung cancer after imaging performed during an illness. She underwent robotic left upper lobectomy for a 35 mm tumor. Pathology showed poorly differentiated adenocarcinoma with clear surgical margins and negative lymph nodes. Her team initially recommended observation and monitoring without adjuvant therapy.

Follow-up PET imaging then identified a large uterine mass measuring about 9 cm. She had no postmenopausal bleeding, discharge, abdominal pain, or palpable mass. The lesion looked fibroid-like but had unusual metabolic activity and areas of necrosis. Atypical fibroid and smooth-muscle tumor of uncertain malignant potential were considered, while metastatic disease was not initially suspected.

After multidisciplinary review, she underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy with peritoneal washings. Surgery and recovery were uncomplicated. Microscopy showed a hyalinised leiomyoma infiltrated by moderately to poorly differentiated adenocarcinoma. The malignant cells were CK7-positive and TTF-1-positive and negative for CK20, PAX8, and GATA3, confirming that the uterine lesion was a metastasis from the lung primary. The ovaries, fallopian tubes, cervix, endometrium, and peritoneal washings were not involved.

A brain MRI was normal. After discussion of treatment options, no further adjuvant therapy was given. She continued three-monthly CT surveillance of the chest, abdomen, and pelvis. Twelve months after surgery, she remained well with normal imaging and no concern for recurrence. She described postoperative pain and some shortness of breath while shopping, but she remained independent and able to complete her usual activities.