Mesothelial Cyst Derived from Chest Wall Pleura Growing after Thoracic Surgery

Journal of Medical Case Reports
15 Apr, 2019 ,

A 63-year-old Japanese woman was referred to our department. She had undergone total hysterectomy for cervical carcinoma and two lung wedge resections for metastatic lung cancer on the upper and lower lobes of her right lung and lower lobe of her left lung. After the thoracic surgery, an intrathoracic chest wall mass was found, which grew gradually. Computed tomography demonstrated a 2.0 × 1.8 cm low-density mass without contrast effect. Magnetic resonance imaging demonstrated a low-intensity mass in T1-weighted imaging and a high-intensity mass in T2-weighted imaging. Thoracoscopic excision of the mass was performed. The cystic mass was thought to be derived from her chest wall and was pathologically diagnosed as mesothelial cyst. Five years after the surgery, she has no evidence of recurrence of the cyst or cervical carcinoma.

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A 63-year-old Japanese woman was referred to our department because of an abnormal shadow at the left side of her chest wall on computed tomography. She had undergone total hysterectomy and radiotherapy for cervical carcinoma 4 years prior. One year after the first surgery, three metastatic lung nodules appeared at the upper lobe of her right lung, the lower lobe of her right lung, and the lower lobe of her left lung. Wedge resection for upper and lower lobe of her right lung was initially performed via three-port thoracoscopic surgery.

Then, wedge resection for the lower lobe of her left lung was performed via eighth intercostal single incisional thoracoscopic surgery. After the surgery, an intrathoracic chest wall mass developed which increased in size gradually. Her gynecologist introduced her to our department for surgical resection of the mass. Her family, including her parents and two sisters, had been healthy and had no inheritable diseases. She had no symptom, drug history, tobacco smoking history, or psychosocial history, and she was a social drinker. She had not received any medications since the mass developed and until admission to our hospital. She had undergone an operation three times as mentioned above and had been a carrier of type B hepatitis.

After her admission to our department, her general condition was good, and there were three operative scars at both sides of her chest and lower abdomen. Her chest sounds were clear and there was no neurological abnormality. She was 151.1 centimeters tall and weighed 49.8 kilograms. Her heart rate was 77/minute, blood pressure was 135/87 mmHg, and body temperature was 36.1 °C. The laboratory findings were white blood cells 5.25 × 103/μL, hemoglobin 12.7 g/dL, and platelets 156 × 103/μL. A liver function test revealed: albumin 4.6 g/dL, aspartate aminotransferase 15 U/L, alanine aminotransferase 13 U/L, and total bilirubin 0.3 mg/dL.

A renal function test revealed blood urea nitrogen 13.6 mg/dL and creatinine 0.79 mg/dL. An electrolyte test revealed sodium 143 mEq/L, potassium 3.8 mEq/L, and chlorine 106 mEq/L. A tumor marker test revealed carcinoembryonic antigen 3.4 ng/mL and squamous cell carcinoma antigen 0.80 ng/mL. Another test revealed positive reaction to type B hepatitis surface antigen and C-reactive protein < 0.1 mg/dL. Computed tomography demonstrated a gradually increasing low-density mass measuring 2.0 × 1.8 cm in diameter. Magnetic resonance imaging demonstrated a low-intensity mass in T1-weighted imaging and a high-intensity mass in T2-weighted imaging. The mass was thought to be a singular cyst; however, this type of cyst was rare and the mass was increasing. Therefore, dissemination of cervical carcinoma could not be excluded, and surgical removal of a part or tissue of the mass was performed.

In the right lateral position, thoracoscopic excision of the mass was done with two ports (3 mm and 2 cm access ports) by two general thoracic surgeons. First the 3 mm port was set at the sixth intercostal space on the inframammary line. Most of her left lung was attached to her chest wall; therefore, the second port was set above the cyst and lysis of adhesions was done. After the lysis, the cystic mass was found adhering to the upper lobe of her left lung. The adhesion of the mass to her lung was not strong and could be separated without injury to the visceral pleura. Therefore, the mass was thought to derive from the chest wall pleura and was resected by adhesiolysis.

The mass was a unilocular cyst containing mucinous fluid. On microscopic examination, the cyst was lined with a single layer of cuboidal epithelium; immunohistochemistry showed positive staining of calretinin and D2-40. Thus, the cyst was diagnosed as mesothelial cyst derived from the chest wall pleura. Five years after the surgery, our patient had no evidence of cyst or cervical carcinoma on computed tomography.