A 14- year-old spayed female miniature Dachshund presented to our hospital with a mass at a previous incision site 7 months after the removal of a lung adenosquamous cell carcinoma (ASCC). Needle tract implantation (NTI) caused by fine needle biopsy was presumed as the cause of the mass. Extended resection of the mass was performed and histopathological examination revealed ASCC and thyroid transcription factor-1 (TTF-1) positivity. No local recurrence was observed; however, the dog died. The incidence of NTI in lung ASCC in dogs is unknown. However, the development of NTI should be monitored.

An old neutered male cat was brought to the hospital with primary signs of anorexia, difficulty breathing, abdominal distension, and purulent rhinorrhea. Clinical examinations showed tension pneumoperitoneum and an intraperitoneal mass of 4 cm in diameter. A needle puncture was performed, releasing 830 mL of gas, at which point breathing improved. A laparotomy was then performed, and a jejunal mass leaking air was excised, followed by abdominal closure. The mass was diagnosed as lymphoma. It is assumed that the lymphoma gave rise to gastrointestinal perforation, which, together with chronic obstructive nasal disease, led to the tension pneumoperitoneum. The pneumoperitoneum did not recur after surgery, and the cat’s condition improved.