CASE REPORT

The authors present the case of a 68-year-old male patient with a history of smoking and chronic cough. A thoracic CT scan was performed and revealed a mass with mediastinal invasion in the left upper lobe and a nodule in the right lung. An abdominal CT scan documented a mass of 40×35 mm in the transition between the body and tail of the pancreatic gland, as well as a nodule in the right adrenal gland, three small liver nodules and a nodule in the right kidney.

An endoscopic ultrasonography (EUS) was performed and identified a heterogeneous, hypoechoic solid lesion, with a clearly defined irregular borders, measuring 17.8 x 20.5 mm. Fine needle biopsy (FNB) was performed (Acquire 22 G, Boston Scientific).

WHAT IS THE MOST LIKELY DIAGNOSIS?

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DISCUSSION

These findings were compatible with pancreatic metastasis of lung cancer. Histopathological analysis revealed small cell high grade neuroendocrine carcinoma, positive for cytokeratin AE1/AE3, CAM 5.2, TTF1, CD56 and synaptophysin and negative for p40 and chromogranin; Ki67 antibody was positive in 40-50% of neoplastic cells. Positivity for TTF1 suggested it was a primary tumor of the lung – small cell lung carcinoma. A final diagnosis of metastatic small cell lung carcinoma was made.

Metastatic tumors of the pancreas are responsible for 1-2% of all pancreatic solid lesions [1]. On EUS they show clearly delimitated borders, and are usually heterogeneous and hypoechoic [1,2]. Renal cell carcinoma is the most common metastatic tumor of the pancreas [2,3]. Other secondary tumors of the pancreas include lung, breast, melanoma, colon, stomach and lymphoma [2,3]. Lung cancer comprises around 18,7% of pancreatic metastatic tumors and small cell lung cancer (SCLC) is the most common histological type [3]. Only 2-3% of lung cancer patients present pancreatic metastases [3]. Most patients have no symptoms related to the pancreatic metastasis, but it can directly invade pancreatic ductal epithelium and may clinically mimic primary pancreatic adenocarcinoma [3]. Pancreatic metastasis generally constitutes a late manifestation of widespread disseminated metastasis in cancer patients, and in SCLC it indicates visceral widespread and it is of ominous prognostic importance [3].

SCLC constitutes 15% of all lung cancers [4]. It is an aggressive neuroendocrine carcinoma with high rate of metastasis and the majority of patients (70%) present with extensive disease [4]. Histologically, SCLC can be further classified into small cell carcinoma and combined subtype [4]. Immunohistochemical findings are positive for CD56 (neural cell adhesion molecule, NCAM), which is the most sensitive for the diagnosis of SCLC [5]. Chromogranin and synaptophysin are true markers of neuroendocrine differentiation and are typical of carcinoid tumors, but may be positive in SCLC [5]. Ki67 is positive in at least 40 to 50% of cells [5]. Positivity for TTF1 is much more frequent in SCLC (90%) but it may also be present in pancreatic neuroendocrine tumors (7%), therefore it cannot be used as the sole criteria for distinguishing lung from pancreatic origin [5,6].

REFERENCES

1. Yamashita Y. and Kitano M., Endoscopic ultrasonography for pancreatic solid lesions, Journal of Medical Ultrasonics, 2020 47(3):377-387.
2. Cortez N., Berzosa M., Mahfouz M., et al, Diagnosis and Treatment of Metastatic Disease to the Pancreas, Journal of Laparoendoscopic & Advanced Surgical Techniques, 2020 30(9):1008-1012.
3. Gonlugur U., Mirici A. and Karaayvaz M., Pancreatic involvement in small cell lung cancer, Radiology and Oncology, 2014 48(1):11-9.
4. Wang Y., Zou S., Zhao Z., et al, New insights into small‐cell lung cancer development and therapy, Cell Biology International, 2020 44:1564–1576.
5. Yatabe Y., Dacic S., Borczuk A.C. et al, Best Practices Recommendations for Diagnostic Immunohistochemistry in Lung Cancer, Thoracic Oncology, 2019 14(3):377–407.
6. Wang J., Trivedi P. and El-Bahrawy M., Positivity rate of TTF-1 on immunohistochemistry in pancreatic neuroendocrine tumors, Pathology International, 2016 66(12):708-709.

AUTHORS

Diogo Bernardo Moura¹, Nuno Nunes¹, Carolina Chálim Rebelo¹, Margarida Flor de Lima¹, Maria Antónia Duarte.

1. Gastroenterology Department, Hospital do Divino Espírito Santo de Ponta Delgada, Ponta Delgada, Portugal.