CASE 18414 Published on 03.01.2024

A case of diffuse pneumonic-type lung adenocarcinoma

Section

Chest imaging

Case Type

Clinical Case

Authors

Sourav Panda 1, Mandal Devashis 2, Singh Binod 1, Rathod Srikant 1

1 Department of Radiology, Healthworld Hospitals, Durgapur, West Bengal, India

2 Department of Pathology, Healthworld Hospitals, Durgapur, West Bengal, India

Patient

54 years, male

Categories
Area of Interest Lung, Oncology ; Imaging Technique CT
Clinical History

A 54-year-old man presented to our hospital with complaints of fever, cough and shortness of breath associated with chronic weight loss and generalized weakness. He was diagnosed as sputum-positive pulmonary tuberculosis outside and was on anti-tubercular drugs since past 2 months.

Imaging Findings

Chest radiograph PA view showed large areas of confluent consolidation in both lungs with few lucent areas seen within the consolidation in right midzone.

Non-contrast CT scan of thorax showed extensive consolidation in both lungs, with intervening ground glass opacities, septal thickening and multiple small cystic/cavitating areas. Some of the consolidations showed internal low-density areas (attenuation values ranging from 1525 HU). There was no associated pleural effusion or significant mediastinal lymphadenopathy.

Patient’s total leucocyte counts and inflammatory markers like C-reactive protein and procalcitonin were within normal limits.

No infective pathogen was identified on microbiological examination, and bronchoalveolar lavage was negative for malignancy. CT-guided biopsy from the left upper lobe consolidation was done, which revealed mucinous adenocarcinoma with lepidic growth. Immunohistochemistry was positive for cytokeratin 7 (CK 7) and was negative for TTF1, CK20, Napsin A, CDX2 and synaptophysin.

Discussion

Lung adenocarcinoma is the most common type of lung cancer [1]. It has a wide variety of imaging appearances on CT scans, and can sometimes present as localized or diffuse lung consolidation, which can be misdiagnosed as pneumonia [2].

Clinically, it is difficult to differentiate pneumonic-type lung adenocarcinoma (PLAC) and infectious pneumonia, as both can present with cough and sputum production [3]. However, infectious pneumonia are frequently associated with fever and elevated inflammatory markers [4].

Several studies have assessed the CT imaging features of pneumonic-type adenocarcinoma [5,6]. Some of the proposed features that can help in differentiating it from infection include irregular air bronchogram sign, bulging interlobular fissure, pseudocavitation, presence of low attenuation areas within the consolidation and CT angiogram sign (seen on contrast-enhanced scans). Irregular air bronchogram sign is seen secondary to lepidic growth or tumour invasion into the bronchi [6,7]. Bulging interlobular fissure sign is seen as result of increased lung volume secondary to mucus production by the tumour cells [8]. Pseudocavitation occurs due to invasion of the tumour cells into bronchial lumen, forming a one-way valve resulting in cyst formation within the consolidation [9]. Consolidation in PLAC tends to have lower attenuation values due to increased mucus production by the tumour cells [7,10].

Diagnosing PLAC requires high degree of suspicion, and it should be kept as one of the imaging differentials in cases with chronic non-healing consolidation. Histopathological correlation is needed to confirm the diagnosis.

Written informed consent for publication has been obtained.

Differential Diagnosis List
Pneumonic-type lung adenocarcinoma
Atypical lung infection like fungal infection
Cryptogenic organizing pneumonia
Final Diagnosis
Pneumonic-type lung adenocarcinoma
Case information
URL: https://www.eurorad.org/case/18414
DOI: 10.35100/eurorad/case.18414
ISSN: 1563-4086
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