Metastases from Occult Breast Cancer: A Case Report of Carcinoma of Unknown Primary Syndrome

Abstract

Carcinoma of unknown primary (CUP) syndrome occurs when metastases from an unknown primary site spread to multiple organs. Occult breast cancer (OBC) is defined as a clinically recognizable metastatic carcinoma from an undetectable primary breast tumor. It accounts for 0.3-1% of all breast cancers, often presenting with lymph node, bone, and skin metastases. Clinical and radiological examinations represent the first steps in the diagnostic algorithm for CUP syndrome from OBC. However, histological and immunohistochemical analyses, multidisciplinary team evaluation, and a multidisciplinary therapy are essential in the diagnosis and treatment of CUP syndrome from OBC. We report the case of a 52-year-old woman who underwent the removal of a parietal skin lesion. The histological and immunohistochemical analyses suggested a breast cancer origin. Clinical assessment and laboratory and radiological examinations did not locate the primary tumor. Hormone therapy was offered to the patient; however, she refused it. After 28 months, the patient reported a right cervical lump, and a total-body positron emission tomography showed dissemination of the disease to the lymph nodes and bone. A CUP syndrome from OBC was diagnosed. A multimodality approach with radiotherapy and hormone and biological therapy was started. At present, 5 years from the first presentation, the patient is asymptomatic despite the disseminated disease.

Keywords: Carcinoma of unknown primary; Metastatic breast cancer; Occult breast cancer.

Fig. 1

aRight breast ultrasound. A 6-mm benign cyst can be observed in the upper external quadrant (BIRADS 2). bLeft breast mammography. A 10-mm calcified lesion of benign appearance can be observed in the lower quadrant (BIRADS 2).

Fig. 2

aHypermetabolic areas in the right cervical lymph nodes. bHypermetabolic right occipital and mastoid lesions. cSlight decrease in metabolic activity in the right cervical lymph nodes, and mastoid metastasis after multimodality therapy.