Calcified peripancreatic lymph nodes in pancreatic and hepatic tuberculosis mimicking pancreatic malignancy

Abstract

Rationale:

Tuberculosis remains a serious menace to the health of people. Isolated hepatic tuberculosis is rare and pancreatic tuberculosis is extremely rare. The preoperative diagnosis of pancreatic tuberculosis remains a great challenge.

Patient concerns:

A 58-year-old Asian woman was referred to our hospital for evaluation of low back pain for 4 years and abdominal pain for 1 month.

Diagnoses:

Computed tomography (CT) of the abdomen showed a hypodense mass in the pancreatic head and neck with abundant calcifications, a hypodense lesion in the liver without calcification, peripancreatic lymphadenopathy, calcifications in some lymph nodes. CT-guided fine needle aspiration biopsy of the hepatic lesion was carried out and the cytological examination revealed hepatic tuberculosis.

Interventions:

The patient was treated with antituberculous therapy for 1 year.

Outcomes:

Low back pain and abdominal pain disappeared 3 months after initial treatment and after 2 year of follow-up, the patient was asymptomatic.

Lessons:

Our data hint that calcifications in both pancreatic lesions and peripancreatic lymph nodes may suggest pancreatic tuberculosis rather than pancreatic malignancy.

1. Introduction

Mycobacterium tuberculosis, still a serious menace to human health, can infect almost any organ in the human body.^[1,2] Nevertheless, hepatic involvement is rare and pancreatic involvement is extremely rare.^[2–4] Majority of cases of pancreatic tuberculosis occur as a part of disseminated tuberculosis, particularly in those with immunodeficiency.^[4,5] The diagnosis of pancreatic tuberculosis can easily be missed or significantly delayed because of its rarity and lack of specificity.^[2,3,6,7] Two articles reported the isolated tuberculosis lesion at liver or around the head of pancreas involved both liver and pancreas.^[8,9] One article reported pancreatic and hepatic tuberculosis without involvement of other organs in an infant.^[10] Here we reported a case of pancreatic and hepatic tuberculosis without involvement of other organs in an immunocompetent person. To our knowledge, similar cases have not been reported. Diagnostic value of calcifications in pancreatic lesions and peripancreatic lymph nodes was discussed here.

2. Case presentation

A 58-year-old Asian woman was referred to our hospital for evaluation of low back pain and abdominal pain. The patient's symptom history was detailed as follows: interminttent low back pain with a tendency to spontaneous regression for 4 years, progressive aggravation of low back pain for 1 month, abdominal pain localized to the epigastrium unrelated to meals for 1 month. The patient denied fever, night sweat, weight loss, cough, vomiting, and jaundice. She denied a history of tuberculosis. Ultrasonography revealed a heteroechoic mass lesion with an unclear irregular border in the pancreatic head, several peripancreatic lymph nodes. Plain computed tomography (CT) of the abdomen showed a mass in the pancreatic head with a slightly low density, an unclear irregular border. Calcifications in the mass were very abundant. Several peripancreatic lymph nodes and calcifications in some were noted. A hypodense lesion in the liver without calcification was observed. Contrast-enhanced CT showed moderate enhancement in the pancreatic mass and a hypodense lesion in the liver with a mild enhancement. Chest x-ray was normal. At the time of admittance to our hospital, physical examination was unremarkable, with epigastric tenderness without guarding. The initial diagnosis was pancreatic malignancy, hepatic and lymphatic metastasis. CT-guided fine needle aspiration biopsy of the hepatic lesion was carried out and the cytological examination revealed hepatic tuberculosis (Fig. 1). The diagnosis of pancreatic and hepatic tuberculosis was confirmed based on the above findings. Subsequently, the patient was treated with antituberculous therapy for 6 months (rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, followed by rifampicin and isoniazid for 4 months). Low back pain and abdominal pain were disappeared 3 months after initial of treatment and after 2 year of follow-up, the patient was asymptomatic.

Figure 1.

(A) The computed tomographic (CT) scout view showed the chest was normal. (B) The pancreas was evaluated with abdominal window settings (width, 350 HU; level, 50 HU). A hypodense mass in the pancreatic neck (the black arrowhead) and calcifications in the lesion (white arrowheads) are observed. (C) The upper abdomen was evaluated with abdominal window settings (width, 350 HU; level, 50 HU). A hypodense mass in the pancreatic head (the black arrowhead) and calcified peripancreatic lymph nodes (white arrowheads) are observed. (D) The upper abdomen was evaluated with liver window settings (width, 150 HU; level, 50 HU). A hypodense mass in the liver (the black arrowhead) and calcified peripancreatic lymph nodes (white arrowheads) are observed. (E) The upper abdomen CT image shows CT-guided fine needle (the gray arrowhead) aspiration biopsy of the hepatic lesion (the black arrowhead) was carried out. Calcified peripancreatic lymph nodes (white arrowheads) are observed. (F) H&E staining of hepatic lesion.

This study was approved by the Ethics Committee of Southwest Hospital, the Third Military Medical University. Informed consent was obtained from the patient for publication of this case report and accompanying images.

3. Discussion

Tuberculosis is still a major public health problem worldwide. In 2015, there were an estimated 10.4 million new (incident) tuberculosis cases, highest incidence being in developing countries.^[1] Isolated hepatic tuberculosis is rare and isolated pancreatic tuberculosis is extremely rare.^[3,4] Although majority of cases occurred as a part of disseminated tuberculosis, about half of patients denied a previous history of tuberculosis infection and more than half showed normal findings on chest radiographs.^[4,5,11,12]

Several excellent articles summarized and reviewed clinical manifestations of pancreatic tuberculosis previously.^{[2,7,12–15]} The clinical manifestations can be diverse and are commonly caused by the mass in pancreas and/or tuberculous toxaemia. They include abdominal or back pain/discomfort, palpable abdominal lump, jaundice, weight loss, anorexia, fever, night sweats, malaise/weakness/fatigue.^{[2,7,12–15]} The diagnosis of pancreatic tuberculosis can easily be missed or significantly delayed because of its rarity and lack of specific manifestations.^[2,7,11] Kim et al^[11] reported that in about 52% of cases, first impression was wrong as pancreatic or peripancreatic malignancy. Some of these patients underwent unnecessary or unproper surgery.^[15,16] Saluja et al^[16] reported that even 2 of 7 pancreatic tuberculosis patients were considered for palliative chemoradiotherapy because of misdiagnosis.

Accurate diagnosis may avoid delays in treatment and unnecessary surgery. Imaging features are helpful for diagnosis of pancreatic tuberculosis.^{[3,6,7,15,17]} Pancreatic tuberculosis may present with a wide range of imaging findings.^{[3,6,7,15,17]} It may present with masses or cystic lesions, mostly in the head or neck of the pancreas. Both solitary lesion and multiple lesions can be observed. Mass lesions in most of cases mimic pancreatic carcinoma.^{[3,6,7,15,17]} CT scans of mass lesions usually demonstrate homogeneous or inhomogeneous consistency with a slightly low density, irregular poorly defined borders. Necrotic cystic areas can be observed in some of patients. Following enhanced scanning, images demonstrate marked enhancement, moderate enhancement, or mild enhancement; they exhibit homogeneous enhancement or inhomogeneous enhancement. Other signs include dilation of the main pancreatic duct and/or upstream biliary, lymphadenopathies surrounding the pancreas, evidence of active tuberculosis in the form of infiltrates, pleural effusion, and so on.^{[3,6,7,15,17]} Vascular invasion of abdominal vessels was often reported as point of distinction between pancreatic tuberculosis and malignancy.^[18] Nevertheless, vascular involvement cannot be used as a criterion to discriminate pancreatic tuberculosis from malignancy, as there are multiple reports of vascular invasion in pancreatic tuberculosis.^[2,18–20] Therefore, these imaging findings are nonspecific.

Calcifications in pancreatic lesions were reported as characteristic in diagnosis of pancreatic tuberculosis.^{[3,6,7,15,17]} Although Xia et al reported that the presence of calcification in numbers as high as 56% patients, others reported a lower ratio of calcification in the lesions (Table 1).^[6,15,17] Nagar et al^[12] reported that in their study, no parenchymal or ductal calcification was seen in pancreatic tuberculosis on CT scan in 32 patients. However, calcifications may be seen in pancreatic malignancies, too (Table 1). More than 80% of pancreatic malignancies are ductal adenocarcinoma.^[21] Some reports indicate the presence of calcification in numbers as high as 21% patients and others have not reported any calcification in the tumors.^[21–23] Acinar cell carcinoma is the second most common type.^[24–27] The ratio of calcification in tumor is from 0 to 50%.^[24,26,27] Neuroendocrine neoplasms account for 1% to 2% of all pancreatic tumors.^[28–31] Calcification in neuroendocrine neoplasms is not rare, especially in nonfunctioning and larger neoplasms.^[28,30,31] Calcification in other rare types of pancreatic tumors is not rare.^[30,32,33] For example, intratumoral calcification has been described as a common feature of solid pseudopapillary carcinomas and the ratio of calcification is >28%.^[32,33] Morphological pattern of calcifications is thought as characteristic in pancreatic tuberculosis.^[3] The morphologies are inconsistent, including irregular, striped, speckled, focal, sand-like calcifications, calcifications forming polycyclic structures, and so on.^{[2,5,6,11,13,15,17,18,34,35]} Calcifications in pancreatic malignancies have been well described previously,^{[21,22,28,30]} although there is a lack of summaries of calcifications in pancreatic tuberculosis, partly because of its rarity. Based on these reports, calcifications may be useful, but not specific imaging criteria for the differentiation of pancreatic tuberculosis from malignancy.^{[3,6,7,15,17,21,22,28,30]}

Table 1.

Ratio of calcifications in pancreatic lesions in literature.

In the case reported here, calcifications in the pancreatic mass were very abundant; moreover, abundant calcifications in several peripancreatic lymph nodes were observed. We searched the literature and no reports on diagnostic value of calcified peripancreatic lymph nodes in pancreatic tuberculosis or malignancy were found. We analyzed case reports on pancreatic tuberculosis and found that majority of cases of pancreatic tuberculosis with calcifications accompanied calcified peripancreatic lymph nodes. From 2010, >50 cases of pancreatic tuberculosis were reported.^{[2,3,5,7,13,14,17–20,34,36–75]} Calcifications in pancreatic lesions were observed in 5 cases in limited images provided in articles.^{[5,13,17,20,48]} In 3 of these 5 cases, calcifications in peripancreatic lymph nodes were observed.^[5,17,48] One case should very likely have calcifications in peripancreatic lymph nodes. Because only 1 contrast CT image was provided in the article, it was difficult to distinguish calcified peripancreatic lymph nodes from blood vessels.^[13] In the left 1 case, it was uncertain whether there were peripancreatic lymphadenopathies with calcifications because of lack of images.^[20] We collected all cases of pancreatic tuberculosis with calcifications as we could and collected 6 cases of pancreatic ductal adenocarcinoma with calcifications as control (Table 2). Calcified peripancreatic lymph nodes accompanied calcifications in pancreatic tuberculosis in 3 of 4 patients. No calcified peripancreatic lymph nodes were observed in 6 cases of pancreatic ductal adenocarcinoma with calcifications. Collectively, these hint that calcifications in both pancreatic lesions and peripancreatic lymph nodes may suggest pancreatic tuberculosis rather than pancreatic malignancy. Tuberculous lymphadenopathy is the most common manifestation of abdominal tuberculosis and majority of cases of pancreatic tuberculosis occur as a part of disseminated tuberculosis.^[4,5,76] It is not surprising that majority of cases of pancreatic tuberculosis with calcifications accompanies calcified peripancreatic lymph nodes. Owing to the limited sample size, further experiments should be carried out to make the conclusion convincing.

Table 2.

Ratio of calcified peripancreatic lymph nodes accompanying pancreatic lesions with calcifications.

4. Conclusion

Pancreatic tuberculosis is extremely rare, with a wide range of nonspecific clinical presentation and image features. The diagnosis of pancreatic tuberculosis can easily be missed or significantly delayed. More than half of cases of pancreatic tuberculosis were initially diagnosed as pancreatic malignancy. Although the presence of calcifications should not dissuade the doctor from raising concern for malignancy and the diagnosis of pancreatic tuberculosis should be bacteriologically or cytologically confirmed, calcifications in both pancreatic lesions and peripancreatic lymph nodes may suggest pancreatic tuberculosis rather than pancreatic malignancy.

Author contributions

Conceptualization: Jianming He.

Data curation: Xi Liang, Xuequan Huang, Jianming He.

Funding acquisition: Xi Liang, Jianming He.

Writing – original draft: Xi Liang, Qian Yang, Jianming He.

Writing – review & editing: Xi Liang, Qian Yang, Jianming He.