Paraneoplastic polymyositis presenting as a clinically occult breast cancer

Abstract

Paraneoplastic syndrome affects less than 1% of cancer patients. Diagnosis of paraneoplastic syndrome with neurological presentation requires screening for an underlying malignancy, including a complete history, physical examination and imaging studies. Treatment often results in symptom stability, rather than improvement. Paraneoplastic polymyositis can precede or instantaneously occur at diagnosis or treatment of a primary tumour, while neurological symptoms can persist even following cancer treatment. We report a rare case of metaplastic breast carcinoma with an unusual presentation of paraneoplastic polymyositis.

Keywords: Breast cancer; Diagnosis; Metaplastic carcinoma; Neurology; Paraneoplastic syndrome.

Figure 1

Discrete moderate focus of uptake in the superior aspect of the left breast and proximal muscles. 304×171mm (96×96 DPI)

Figure 2

Left breast mammogram, craniocaudal view, of the oval lesion. 210×442mm (96×96 DPI)

Figure 3

Left breast mammogram, mediolateral oblique view. At the 12 o'clock position, there is a 12.6mm oval lesion, which contains some echogenic calcifications. 316×521mm (96×96 DPI)

Figure 4

At the 12 o'clock position, there are some echogenic calcifications. This is graded as R3 U4. Ultrasound in the low left axilla shows a lymph node, which has a slightly thickened cortex measuring up to 1.7mm. The length of the lymph node is 10.3mm. The lymph nodes superior to this are, overall, less prominent. 213×161mm (96×96 DPI)