[Endoscopic ultrasound-guided fine-needle biopsy for diagnosis of pancreatic metastases producing parathyroid hormone-related protein].

A 66-year-old man was admitted to our department with hypercalcemia, pancreatic and liver tumors, and periportal lymph node enlargement. Contrast-enhanced computed tomography revealed a tumor in the pancreatic tail and the right hepatic lobe along with periportal lymphadenopathy. Laboratory data revealed hypercalcemia and high serum parathyroid hormone-related protein (PTHrP) levels. Using a 22-gauge Franseen needle, we performed endoscopic ultrasonography-guided fine-needle biopsy of the pancreatic mass and an enlarged lymph node. Histopathological examination of the biopsy specimen revealed moderately to well-differentiated pancreatic adenocarcinoma with poorly differentiated squamous cell elements, as well as squamous cell carcinoma of the lymph node. Immunohistochemical examination showed that the pancreatic tissue was weakly immunopositive and the lymph node was strongly immunopositive for anti-PTHrP antibody. We diagnosed the patient with pancreatic adenosquamous carcinoma with liver and lymph node metastasis, associated with hypercalcemia of malignancy secondary to PTHrP secretion. We administered systemic chemotherapy comprising gemcitabine and nab-paclitaxel. Unfortunately, the patient died 8 months after being diagnosed with this malignancy. PTHrP-producing adenosquamous carcinoma of the pancreas is rare;only 14 cases are reported in the literature. Based on immunohistochemical evaluation, this case report suggests that metastatic lymph nodes may lead to the overproduction of PTHrP in such cases.