Malignant pleural effusion from papillary thyroid carcinoma diagnosed by pleural effusion cytology: A case report

Metastatic papillary thyroid carcinoma in pleural effusion: a case report and review of the literature

INTRODUCTION

Papillary thyroid carcinoma accounts for the most common type of thyroid cancer of well-differentiated type. Papillary thyroid carcinoma is featured by biologically low-grade and less aggressive tumors with a survival rate of 10 years in most of the diagnosed cases. Papillary thyroid carcinoma can be presented with the involvement of cervical lymph nodes in about 50% of the patients, yet distant spread is very uncommon.

CASE PRESENTATION

Herein, we discuss a Saudi male patient in his early 50s with a history of papillary thyroid carcinoma who presented to the emergency department complaining of shortness of breath and a radiological finding of hydrothorax. Cytologic examination together with immune-histochemical staining and molecular studies of pleural effusion aspiration concluded the definitive diagnosis of metastatic papillary thyroid carcinoma in the pleural space.

CONCLUSIONS

Papillary thyroid carcinoma seldom causes metastatic niches in the pleural space; this is a rare clinical presentation, nevertheless, a differential diagnosis of thyroid metastasis needs to be excluded. A definitive diagnosis of metastatic papillary thyroid carcinoma can be made using clinical presentation, cytologic examination, immunohistochemical investigation, and molecular testing. The most common mutation found in papillary thyroid carcinoma cases is the V600E mutation found in the BRAF gene, yet these patients have a relatively low probability of cancer recurrence. Patients with papillary thyroid carcinoma who have the BRAF mutation frequently experience metastases and relapses of the disease after the cancer has progressed aggressively. To help with therapy planning and the introduction of BRAF inhibitors, genetic testing for BRAF mutation may therefore prove to be a useful tool, especially in cases of aggressive subtypes of TC.

Pleural effusion as a novel prognostic factor in metastatic thyroid carcinoma

OBJECTIVE

To identify novel prognostic risk factors and compare them with other known prognostic risk factors in follicular-cell-derived thyroid carcinoma (FDTC) with distant metastases.

METHODS

A retrospective review was conducted of adult patients with metastatic FDTC seen at a tertiary care center between January 1990 and December 2010. A 15-year Kaplan-Meier survival estimate was created for overall survival (OS) and cancer-specific survival (CSS). Hazard ratios (HR) and P values from Cox proportional hazard models were used with a 95% CI.

RESULTS

There were 143 patients (60.1% male, 39.9% female), of whom 104 (72.7%) patients had papillary, 30 (21.0%) had follicular, 5 (3.5%) had poorly differentiated, and 4 (2.8%) had Hürthle cell cancers. Median length of follow-up was 80.0 months (range 1.0-564.0). The 15-year mortality rate was 32.2% and cancer-specific mortality was 25.2%, with OS and CSS having the same risk factors. Lung was the most common site of metastases in 53 patients (37.1%), and patients with pleural effusions had significantly lower CSS (HR = 5.21, CI = 1.79-15.12). Additional risk factors for a decreased CSS included: older age upon diagnosis (>45 years, HR = 4.15, CI = 1.43-12.02), multiple metastatic locations (HR = 3.75, CI = 1.32-10.67), and incomplete/unknown tumor resection (HR = 2.35, CI = 1.18-4.67).

CONCLUSION

This study is the first to demonstrate that pleural effusion is a poor prognostic sign in patients with FDTC with distant metastases and compare this risk with other accepted prognostic variables.

Pleural fluid due to papillary thyroid cancer

We report herein a rare case of massive pleural effusion caused by papillary thyroid cancer, which was accompanied by multiple pulmonary metastasis. A 91-year-old male patient presented with shortness of breath due to massive right pleural fluid. Cytological specimens, which were obtained from pleural fluid by thoracentesis, and was consistent with that observed in surgically resected thyroid cancer 6-year previously. Immunocytochemical staining of the cells was positive for cytokeratin (CK)-7, CK-19, and positive for thyroglobulin. Massive pleural fluid due to a metastatic from papillary thyroid cancer is very rare but may develop in long-term survivors with this disease as observed in this case.

Label-free microfluidic chip for the identification of mesothelial cell clusters in pleural effusion

The detection of tumor cells and clusters in pleural effusion assists in the diagnosis of lung cancer. The proportion of tumor cells and clusters to the total number of cells in each patient varies substantially due to individual differences and the severity of the disease. The identification of one tumor cell or cluster from a large number of pleural effusions is the main challenge for hydrothorax tumor cell detection techniques. In the present study, by using A549 lung cancer and Met-5A mesothelial cell lines, a label-free microfluidic chip based on cell cluster size was designed. By setting the parameters of the chip, individual cells and clusters were able to enter different microfluidic channels. Subsequent to non-specific staining, the recovered components were stained using acridine orange (AO). A charge-coupled device camera was used to captured images of the cell, and the features of these cells were analyzed in their R and G channels using Matlab software to establish the characteristics and finally differentiate between the tumor and non-tumor cell or clusters. According to the results, when inlet A and B were under a velocity of 10 and 8.5 ml/h, respectively, the tumor cell clusters were successfully collected through microfluidic channels III–V, with a recovery rate of ~80%. Subsequent to staining with AO, the feature values in the R and G channels were identified, and initial differentiation was achieved. The present study combined the microfluidic chip, which is based on cluster size, with a computer identification method for pleural effusion. The successful differentiation of tumor cell clusters from non-tumor clusters provides the basis for the identification of tumor clusters in hydrothorax.