Histologic Changes--Tumor

The tumor is an adenocarcinoma because it lines spaces, forms glands, and produces mucin. The lack of cohesion of the cells is a postmortem artefact.

At the center of the tumor was a dense scar. Although it was formerly thought that such scars preceded and predisposed to the tumor, it is now believed that the scar develops as a result of the tumor.

Given the size of the tumor and the known slow doubling time of adenocarcinomas, it is clear that the tumor predated the onset of this patient's rash and respiratory problems.

Below is a PAS-D stain for neutral mucin (A), which shows red cytoplasmic mucin droplets in tumor cells. The target-like appearance of the droplet to the left is characteristic. B shows additional cytoplasmic inclusions that did not stain with the PAS-D stain. They were present in many tumor cells. Their significance is not known. It is possible that these inclusions are related in some way to the DM.

A

B

This subpleural metastatic deposit of tumor shows gland formation. The arrow points to tumor in a lymphatic, the presumed route of the tumor to this site.

No appreciable lymphoid response to the tumor was present in the primary site or in the metastases, providing no support for an immunologic reaction to tumor that might have triggered the DM.

Clinical summary Discussion

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