A 70 years old male, presented with chronic dry cough for three months and a past medical history of renal stone and benign prostatic hyperplasia (BPH), referred to our clinic. Negative history of any thoracic surgery or other underlying health conditions. Inflammatory blood markers such as erythrocyte sedimentation rate and C-reactive protein were increased. His laboratory results were normal except; low hemoglobin level and increased prostatic specific antigen level.
The abdominopelvic ultrasonography report indicated a 31 mm cortical cyst in the right kidney, mild pleural effusion on the right side, and enlarged prostate (43 ccs) with a homogenous echo pattern. The CT imaging without contrast showed a focal grand-glass opacity (crazy paving appearance) at the apex of the right lung, at least five sub-pleural, mediastinal base pulmonary nodules with a maximum size of 9 mm, and a pulmonary nodule of 18 mm*16 mm at the right lower lobe of the lung.
Fine nodular aspiration (FNA) was performed on right pulmonary nodules. The microscopic evaluation of FNA results showed cellular smears composed of many isolated groups, a cluster of atypical epithelial cells, and macrophages in a bloody background with high malignancy
A chest CT scan with IV contrast was performed for further evaluations, which showed a 29 mm pleural base irregular nodule in the apex of the right lung with superior soft tissue extension without significant ribs or vascular invasion. Also, an 18 mm nodule in the base of the right lung base, multiple pleural base nodules up to 12mm, was seen in the right lung, highly suspicious of a metastatic lesion. Based on these findings, the patient was scheduled for surgery.
After prepping and draping, under general anesthesia, the skin was incised through a standard lateral thoracotomy incision. The pleural cavity was entered through the 4th intercostal space with adhesion presenting between parietal and visceral pleura, and partial parietal pleurectomy was done, then the pleural cavity was evaluated. A mass lesion was present in the right upper lobe; therefore, wedge resection was performed on the right upper lobe, followed by parietal pleurectomy. The tissues were sent to the pathologist, and the patient was discharged with an uneventful post operation course.
Based on the lesion's pathological evaluation, the gross evaluation showed multiple irregular fragments of creamy- gray and yellow rubbery tissue, measuring (5*4*1.3) cm, demonstrating multiple benign lesions, consistent with benign multicystic mesothelioma. Immunohistochemistry (IHC) study was performed to confirm the diagnosis and roll out other differential diagnoses such as alveolar adenoma and sclerosing hemangioma, which demonstrated CK7 positive, CD34 negative, Calretinin positive, TTF1 negative, EMA weak, P53 negative; which were in favor of "multicystic mesothelioma."
Three months after surgery, a follow-up spiral chest CT scan was done, demonstrating evidence of loculated pleural effusion at the right lower lobe periphery. After injection of contrast, evidence of small wall enhancement with the possibility of empyema formation was diagnosed. Also, there were multiple enhancing nodules in the pleural on the right side scattered in both upper and lower zones of the chest's right side. According to this finding possibility of multicystic mesotheliomas was considered. Also, a mass lesion noted at the right apex of the lung with some heterogeneous enhancement measuring 3*2 cm in size seems to be mesothelioma's focuses. Multiple similar nodularities in the pleural cavity's supradiaphragmatic area were noted due to multiple nodules of mesothelioma.
The specimens from our patient's lesion were obtained and sent to the pathology lab, which demonstrated multiple cysts and cystic nature of this lesion with thin walls, lined with one layer of mesothelial cells, which has flattened to cuboidal morphology (Fig. 1), which these findings were in favor of multicystic mesothelioma.