Skeletal muscle metastases as the initial manifestation of an unknown primary lung cancer detected on F-18 fluorodeoxyglucose positron emission tomography/computed tomography :Kanhaiyalal Agrawal, Anish Bhattacharya, Navneet Singh, Chidambaram Natarajan Balasubramanian Harisankar, Bhagwant Rai Mittal, Indian Journal of Nuclear Medicine

CASE REPORT
Year : 2013 | Volume : 28 | Issue : 1 | Page : 34--35

Skeletal muscle metastases as the initial manifestation of an unknown primary lung cancer detected on F-18 fluorodeoxyglucose positron emission tomography/computed tomography

Kanhaiyalal Agrawal¹, Anish Bhattacharya¹, Navneet Singh², Chidambaram Natarajan Balasubramanian Harisankar¹, Bhagwant Rai Mittal¹,
¹ Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
² Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
Anish Bhattacharya
Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
India

Abstract

Skeletal muscle metastasis as the initial presentation of the unknown primary lung cancer is unusual. A 65-year-old male patient presented with pain and swelling of the right forearm. Fine needle aspiration of the swelling revealed metastatic squamous cell carcinoma. The patient underwent whole body F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to identify the site of the primary malignancy. The authors present PET/ CT images showing FDG-avid metastases to the skeletal muscles along with a previously unknown primary tumor in the right lung, in a patient presenting with initial muscular symptoms without any pulmonary manifestations.

How to cite this article:
Agrawal K, Bhattacharya A, Singh N, Harisankar CN, Mittal BR. Skeletal muscle metastases as the initial manifestation of an unknown primary lung cancer detected on F-18 fluorodeoxyglucose positron emission tomography/computed tomography.Indian J Nucl Med 2013;28:34-35

How to cite this URL:
Agrawal K, Bhattacharya A, Singh N, Harisankar CN, Mittal BR. Skeletal muscle metastases as the initial manifestation of an unknown primary lung cancer detected on F-18 fluorodeoxyglucose positron emission tomography/computed tomography. Indian J Nucl Med [serial online] 2013 [cited 2023 Mar 31 ];28:34-35
Available from: https://www.ijnm.in/text.asp?2013/28/1/34/116814

Full Text

Introduction

Skeletal muscle metastasis as the initial presentation of an unknown primary lung cancer is unusual. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging is useful in the identification of primary in carcinoma of unknown origin. We describe a patient showing FDG-avid metastases to the skeletal muscles along with a previously unknown primary tumor in the right lung, in a patient presenting with initial muscular symptoms without any pulmonary manifestations.

Case Report

A 65-year-old male presented with pain and swelling of the right forearm. Fine needle aspiration cytology of the swelling showed metastatic squamous cell carcinoma. The patient underwent a whole body F-18 FDG PET/CT to identify the site of the primary malignancy. Increased FDG avidity (standardized uptake value [SUV max ] 9.0) was detected in an irregular heterogeneously enhancing soft-tissue mass in the right paravertebral region in the upper lobe of the right lung with a focus of calcification within the mass [Figure 1]b and d, white arrow]. Abnormal FDG uptake was also noted in a presacral mass [Figure 1]c and e, the bulky left adrenal gland, several dorsal vertebrae and multiple lesions in the trapezius [Figure 1]b and d, red arrow], right brachioradialis [Figure 2], deltoid, and right external oblique muscles [Figure 3], suggestive of metastatic involvement. A diagnosis of primary squamous cell carcinoma of the lung was pathologically confirmed. The patient was treated with 4 cycles of chemotherapy, after which significant decrease in FDG uptake (SUV max = 5.1) was seen in the primary as well as the right brachioradialis muscle lesion (not shown here).{Figure 1}{Figure 2}{Figure 3}

Discussion

Skeletal muscles are uncommon site of hematogenous metastases from epithelial neoplasms. Solitary muscle metastasis has been previously reported in lung cancer. [1] Tuoheti et al. found that only 4 patients (0.16%) among 2,557 patients with lung cancer developed metastasis to the skeletal muscle. [2] Most frequent muscle involvement is seen in the thigh, iliopsoas and paraspinous muscles. [3] Whole-body FDG PET/CT imaging is useful in detection of muscle metastases in lung cancer patients. [4] Multiple muscle metastases from lung cancer are rare, and FDG PET/CT imaging is useful in the identification of unsuspected metastatic sites. [5] Primary presentation of a skeletal muscle metastasis, such as in our case, remains an unusual occurrence. [3],[6],[7],[8],[9] The present case, where the initial presentation was of metastatic muscular involvement, highlights the role of FDG PET/CT in tracing the location of primary lung malignancy and unsuspected sites of multiple muscle metastases in a patient with muscle metastases of unknown primary.

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