Case-of-the-Month - January 1997

Contributed by:

Mariano Alvira, M.D.
Department of Pathology
Middletown Regional Hospital
Middletown, Ohio 45042

DETERMINING THE PRIMARY SITE FOR A METASTATIC CARCINOMA

A 92 year old white female presented with a malignant pleural effusion. A mammogram done a year ago showed a suspicious lesion in her left breast. A biopsy was not done. The clinical impression was that of metastatic breast carcinoma. Determination of CEA in the fluid supernatant was 1.1 ng/ml. CA19-9 determination in the fluid was 10 ng/ml. Cytology (Figure 1) showed balls and clusters of partially degenerated, atypical neoplastic cells that were thought to represent metastatic breast carcinoma. This was further reinforced by the positive nuclear staining for estrogen (Figure 2) and progesterone (Figure 3) receptors. Tumor markers in malignant effusions are very helpful since they are greatly elevated in metastatic carcinomas, (with some exceptions!), and negative in mesotheliomas. Mesotheliomas can also account for large malignant cells that are similar to the groups and clusters of neoplastic cells in this patient's pleural effusion. These large, malignant cells are indistinguishable from the cells of a large cell carcinoma on routine H & E stains. Since this patient's pleural effusion had normal levels of CEA and CA19-9 and contained large malignant cells, the possibility of a diagnosis of mesothelioma was also considered. Electron microscopy was done because the large size and pattern of carcinoma cells were not typical of metastases from a primary breast carcinoma.
Figure 1. Cell block of fine needle aspirate (H&E).	Figure 2. Immunostaining for estrogen receptors (positive nuclei black).	Figure 3. Immunostaining for progesterone receptors (positive nuclei black).

Electron microscopy

1997 List of Monthly Cases