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December 2022

Signalment: 11-y-old male entire West Highland White Terrier dog.

MD: Peritoneal carcinomatosis with abdominal hematic effusion.

Comment: fragments from testicular parenchyma, epididymis and spermatic cord with whitish, hard foci were initially submitted from this patient. A diagnosis of signet-ring carcinoma was achieved by histological evaluation. The most common location of this entity is the stomach, but this might be found in other organs. There are also rare cases reported in human literature of so-called “metastatic signet-ring carcinoma of unknown primary site (CUP)” to the testis. This syndrome is characterized by the presence of metastatic disease without establishment of the primary site. A month later, the dog was euthanized because of deteriorating clinical signs. There was evidence of peritoneal carcinomatosis (Fig.1) associated with a thickening of the intestinal wall (Fig.2), regarded as the primary site. In this case we were able to identify the primary tumor, but an extensive investigation throughout necropsy was needed. Failure to identify the primary site would have led to the establishment of CUP diagnosis.

Figure 1

Figure 2



1.Munday JS, Löhr CV, Kiupel M. Tumors of the alimentary tract. In: Meuten DJ, ed. Tumors in Domestic Animals. 5th ed. Wiley Blackwell, 2017: 499-601.

2.Kollas A, Zarkavelis G, Goussia A, Kafantari A, Batistatou A, Evangelou Z, Sintou E, Pavlidis N. Testicular signet-ring cell metastasis from a carcinoma of unknown primary site: a case report and literature review. Case Rep Oncol Med 2016; 2016: 7010173.

Contributor:Vittoria Castiglioni, Idexx Laboratories Italia; vittoria-castiglioni@idexx.com

Acknowledgement: Clinica Veterinaria Monte Rosa, Castelletto Sopra Ticino (NO), Italy