Case No.: W-001 Quiz

Diagnosis: Metastatic adenocarcinoma, lung origin

Organ: Vertebral column, L2

Last Updated: 12/22/2009

	CT: The osteolytic lesion is highlighted by the arrow.
Hematoxylin & eosin	Area 1: Under low-magnification, small fragments of bone (arrow) surrounded by atypical cells are present in this biopsy specimen.
Hematoxylin & eosin	Area 1: The bone fragments (B) are surrounded by large, pleomorphic, epithelial cells (T) that are diagnostic morphologically for a metastatic non-small cell carcinoma. Many mitotic figures are present (arrows). Note that some of the cells around the bone chips has elongated or a spindle appearance.
Hematoxylin & eosin	Area 1: In the same specimen, there are clusters of pleomorphic epithelial cells not attached to the bone. In these areas, the epithelial nature of a carcinoma is most clearly seen.

History: The patient was a 58 year-old woman with low back pain for about 5 months duration. There was no history of fall, trauma, or other events that precipitated the pain. The patient was a house wife and smoke about 1 pack of cigarettes a day but with denied the use of alcohol or drug. On CT imaging, an osteolytic lesion was demonstrated in the posterior elements of her L2 spine. A needle biopsy was performed and yielded the the current specimen.

Histologic Highlights of this Case:

Due to the presence of bone fragments, the specimen was decalcified with acid after fixation with formalin for histological sections.
The specimen is composed mainly of blood. In some small areas of the specimen, there are bone fragments surrounded by large, atypical, epithelial cells. The morphology is most consistent with a metastatic non-small cell carcinoma.
Morphology alone cannot always determine the origin of a metastatic tumor. Immunohistochemistry was performed in this case. The overall profile is as follow:
Pancytokeratin, cytokeratin 7, thyroid transcription factor 1 (TTF-1): positive in tumor cells.
Cytokeratin 20: Negative in tumor cells.
Gross cystic disease fluid protein 15 (GCDFP-15): Negative in tumor cells.
This profile suggest that the tumor is most likely a metastatic adenocarcinoma of lung origin. The negative GCDFP15 result rule out the possibility of metastatic breast carcinoma in this case.

Bonus Images:

Hematoxylin & eosin	Additional high-magnification images: Note the relationship between the bone (B) and tumor cells (arrows).
Hematoxylin & eosin	Additional high-magnification images: Note the enlarged nuclei with nucleoli (arrow).
Immunohistochemistry	Pancytokeratin (AE1/AE3): Note the positive cells (brown cells) and bone (B). Most carcinomas are positive for this combination of cytokeratin on immunohistochemistry.
Immunohistochemistry	Cytokeratin 7: Cytokeratin 7 is often but not always positive in adenocarcinoma and small cell carcinoma arising from the lung. In contrast, cytokeratin 20 is often negative in these tumors.
Immunohistochemistry	Thyroid transcription factor 1 (TTF-1): TTF-1 is often positive in adenocarcinoma and small cell carcinoma of the lung. They are also positive in tumors of the thyroid gland. In contrast to the staining in AE1/AE3 and cytokeratin 7, the positive staining in TTF-1 is in the nuclei.

Original slide is contributed by Dr. Kar-Ming Fung, University of Oklahoma Health Sciences Center, Oklahoma, U.S.A.

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