Cytologic Features and Immunocytochemical Profiles of Malignant Effusions with Metastatic Papillary Thyroid Carcinoma: A Case Series from a Single Institution

Malignant effusions secondary to metastatic thyroid carcinomas: A review of 15 cases

BACKGROUND

Malignant effusions secondary to thyroid carcinomas are rare, and publications on this topic are limited. This study presents a large cohort of thyroid carcinomas involving effusion cytology.

METHODS

A 20-year computerized search for fluid cytology diagnosed with thyroid malignancy was performed. The following data were collected: patients' demographics, clinical findings, and histologic diagnoses. The cytology slides and ancillary tests were reviewed.

RESULTS

Among 47,593 specimens, 15 thyroid carcinomas involving the pleural fluid from 11 patients were found. There were six males and five females with a mean age of 72 years. Ten patients with available follow-up died of their disease. Papillary thyroid carcinoma (PTC) was the only histologic type. Ten cytology cases were available for review. The cytologic findings common to all cases were nonspecific (clusters/three-dimensional architecture, enlarged irregular nuclei, and scant to abundant to vacuolated cytoplasm). The classic PTC features were not present in all cases (fine/powdery chromatin [80%], micronucleoli [70%], nuclear grooves [50%], papillary-like architecture [40%], psammoma bodies [40%], and pseudo-nuclear inclusions [20%; present on the cell block only]). In 11 of the 15 cases, the diagnosis was rendered with immunohistochemical stains performed on the cell block (paired box 8, thyroid transcription factor 1, and thyroglobulin). In four of the 15 cases, the cytologic diagnosis was made after a comparison with prior surgical pathology or fluid cytology.

CONCLUSIONS

PTC is the most common histologic type of thyroid malignancy involving pleural effusion. Because the cytologic findings are nonspecific and classic PTC features are not always present, the clinical history in conjunction with immunohistochemical stains is helpful in arriving at the correct diagnosis.

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.

Diagnosis and categorization of malignant effusions: A 6-year review from a single academic institution

BACKGROUND

Cytologic detection of malignant cells in pleural, peritoneal, or pericardial effusion most likely indicates advanced stage of malignant disease. There are a few studies updating the categorization of malignant effusions.

METHODS

The electronic pathology database was searched to identify consecutive cases of malignant effusion during a 6-year period. Patient age and gender, origins of known malignancy, and cytologic diagnoses were recorded and summarized.

RESULTS

A total of 1059 specimens included 561 (53%) pleural, 441 (41.6%) peritoneal, and 57 (5.4%) pericardial fluids. Most of the pleural (516, 92.0%), peritoneal (418, 94.8%), and pericardial (53, 93.0%) specimens were derived from patients with a single known malignancy. More common origins involving pleural fluid were lung (152, 27.1%) followed by breast (103, 18.4%) and gastrointestinal tract (76, 13.5%). The most common etiology for women and men was breast (102, 30.8%) and lung (67, 36.2%), respectively. More common origins involving peritoneal fluid were gastrointestinal (158, 35.8%) and gynecologic (156, 35.4%) tracts, and breast (46, 10.4%). The most common etiology for women and men was Mullerian (156, 55.5%) and gastrointestinal tract (94, 68.6%), respectively. Most common origins involving the pericardial fluid were breast (20, 37.7%) and lung (17, 29.8%). Breast and lung were the most common etiology for women (20, 57.1%) and men (8, 44.4%), respectively.

CONCLUSIONS

Breast and lung remain to be the most common origin of both malignant pleural and pericardial effusion for women and men, respectively. The most common origin involving peritoneal effusion is Mullerian for women and gastrointestinal tract for men.

Metastatic thyroid carcinoma presenting as malignant pleural effusion: A cytologic review of 5 cases

Malignant pleural effusion can be a manifestation of many malignancies. Involvement of pleural fluid by metatstatic thyroid carcinoma, though reported, is relatively rare. We present 5 cases of metastatic thyroid carcinoma involving the pleural fluid. The diagnosis of thyroid carcinoma in pleural fluid can be particularly challenging as thyroid transcription factor -1 (TTF-1) which is a marker for carcinoma of thyroid origin is also positive in lung adenocarcinomas (which are more frequently associated with pleural effusions) and thyroglobulin (TG) can often be negative in poorly differentiated/analplastic thyroid carcinomas. In our experience, PAX8 is a particularly useful marker in making the distinction. The diagnosis of metastatic thyroid carcinoma in pleural fluid can be challenging and knowledge of the clinical context and supporting immunohistochemical stains is essential for making the right diagnosis. Diagn. Cytopathol. 2016;44:1085-1089. © 2016 Wiley Periodicals, Inc.