# Soft tissue tumor of metastatic non-small cell lung carcinoma: A rare case report

## TL;DR

A rare case of non-small cell lung cancer metastasizing to soft tissue in the arm is reported, highlighting the importance of considering such metastases in lung cancer patients.

## Contribution

This case report emphasizes the rarity and diagnostic challenges of soft tissue metastasis from lung cancer, offering insights into clinical management.

## Key findings

- Soft tissue metastasis from lung cancer is rare but should be considered in patients with palpable masses.
- Diagnosis can be confirmed through clinical, radiological, and histological evaluation without immunohistochemistry in select cases.
- Wide excision of the tumor followed by chemotherapy and radiotherapy led to remission in this patient.

## Abstract

It is estimated that 1 out of 5 patients with cancer will experience bone metastasis. With non-small cell lung cancer by itself having 220.000 reported cases per year, but the prevalence of soft tissue metastasis from lung cancer is only 2.3 % making it commonly overlooked as a possible metastasis site.

Male presents with a lump and pain on the right upper arm. A 8 cm × 8 cm mass was palpated under the biceps. CT-scan showed a lung lesion on the anterior segment. Shoulder MRI showed a dense, lobulated, and indefinitely demarcated soft tissue mass approximately 5.6 cm × 7.8 cm × 8.8 cm. The patient was treated with wide excision of the tumor. Core biopsy showed a metastatic adenosquamous carcinoma with suspected primary lesion from the respiratory tract. Treatment with targeted chemotherapy and radiotherapy were then done to the patient. The patient was discharged without any complications and is still at remission at the 6 months post-operative checkup.

Soft tissue metastasis of lung cancer cell is a rare but a very real phenomenon. In our case the diagnosis of the soft tissue mass as a metastasis from the lungs was decided on a clinical, physical, radiological, and histological basis without using immunohistochemistry.

MRI, biopsy, and immunohistochemistry are traditionally needed to confirm the diagnosis but in select cases, radiological and microscopic examinations along with clinical correlation are enough to ascertain the diagnosis. While it is rare, a soft tissue metastasis should always be suspected in lung cancer patients that have a palpable mass.

•Metastasis bone disease is one of the most common causes of bone malignancies,•Metastasis to the muscle or soft tissue is rare•Any soft tissue mass found in patient with lung cancer should warrant further examination•Many factors are associated with musculoskeletal metastasis, but none have been established•Established muscle metastasis can be treated with wide excisions of tumor

Metastasis bone disease is one of the most common causes of bone malignancies,

Metastasis to the muscle or soft tissue is rare

Any soft tissue mass found in patient with lung cancer should warrant further examination

Many factors are associated with musculoskeletal metastasis, but none have been established

Established muscle metastasis can be treated with wide excisions of tumor