Endocrine Abstracts

JOINT1734

Introduction: The most common sites of distant metastasis from bronchial cancer are lung, liver, bone, adrenal and central nervous system. While muscle metastases are rarely described in the literature. In clinical series, muscle is metastatic site in 0.03 to 0.16% of cancers while autopsy series reported a frequency up to 16%. This difference is due to the clinical aspects which are variable, This may lead to misdiagnosis.

Objective: Interest in the completion of SPECT/CT slices complementary to planar images in the presence of clinical signs of calls with a focus of hyperfixation to planar images of bone scintigraphy in the diagnosis and therapeutic guidance.

Materials and methods: We report the case of a patient referred for an extension assessment of bronchial neoplasia. A bone scan completed with SPECT/CT was performed with a GE NM/CT DISCOVERY 670 Gamma camera.

Results: A 79-year-old patient with firm, painful swelling of the groin that was initially inconclusive on scintigraphy. Whereas, 2 years later, a control scan was performed to establish a hyperfixation focus of the metaphyseal regionproximal diaphysal of the left femur corresponding to bone lysis contiguous to an adjacent soft tissue mass extending into the spinal canal on SPECT/CT slices. The ultrasound-guided biopsy concluded an infiltration of muscle by a neoplastic malignant proliferation of epithelial nature (adenocarcinoma) with positivity to thyroid transcription factor 1 (TTF1) and CK (AE1/AE3) consistent with a pulmonary origin which confirms the loco-regional extension of muscle ass to adjacent bone. The patient was treated with chemotherapy using gemcitabine and carboplatin.

Discussion: These metastases often occur during the course of a known cancer and are rarely as revealing as in our case. SPECT/CT sections confirm the presence of muscle mass without being able to decide on its metastatic nature. They were used to guide the biopsy. In our patient, the ultrasound biopsy confirmed the diagnosis of muscle metastasis of a pulmonary adenocarcinoma due to the positivity of tumor cells at TTF1. The SPECT/CT scan of the region with signs of call during the course of a bronchial cancer allowed to correct the therapeutic conduct in the presence of skeletal muscle metastasis that escaped radiological exploration.

Conclusion: Skeletal muscle metastasis is a rare event in the course of bronchial cancer. The clinical presentation is often misleading leading to a delay in diagnosis and inappropriate therapeutic conduct. Interest in performing SPECT/CT slices in the presence of clinical signs with hyperfixation focus.