Unusual presentation of an invasive mucinous adenocarcinoma (aka-BAC) as cavitating pneumonia: a case report

¹Division of Pulmonology, Chris Hani Baragwanath Academic Hospital, University of Witwatersrand, Johannesburg, South Africa, ²Department of Internal Medicine, Mbeya Zonal Referral Hospital, University of Dar es Salaam Mbeya, College of Health and Allied Sciences (UDSM-MCHAS), Mbeya, Tanzania, ³Netcare Olivedale Hospital, Olivedale, Randburg, South Africa

^&Corresponding author
Mwakyula Habakkuk Issakwisa, Department of Internal Medicine, Mbeya Zonal Referral Hospital, University of Dar es Salaam Mbeya, College of Health and Allied Sciences (UDSM-MCHAS), Mbeya, Tanzania

Introduction    

Bronchoalveolar carcinoma (BAC), now termed pulmonary mucinous adenocarcinoma, is a non-small cell lung cancer (NSCLC) and represents 6.5% of pulmonary neoplasms [1]. This tumour typically presents as a solitary lesion, consolidation and diffuse pattern. The rationale for writing the case stems from the unusual radiological presentation of the BAC, which is not in keeping with typically described patterns, namely solitary lesion, consolidation and diffuse disease [2]. More importantly, cavitating pneumonia in a patient with no risk factors for malignancy in our setting with a high burden of tuberculosis and other necrotising infections will most of the time be treated as an infective process as in this case, leading to delays in diagnosis with resultant devastating outcomes. Lastly, we want to highlight the typical patient profile of the patients with BAC, which does not conform to most lung malignancies, usually in younger females and non-smokers with no apparent risk factors for malignancy [3].

Patient and observation     

Patient information: a 50-year-old black African female without a background history of smoking was referred from a private health care facility after a one-year history of coughing mucopurulent sputum, episodic haemoptysis and significant weight loss. She accounts for having been treated with several antibiotics and a complete course of antituberculous drugs without any symptomatic improvement.

Clinical findings: her physical examination was significant for tachypnoea, temporal wasting and bilateral crackles.

Timeline of current episode: this patient had attended several hospitals in different settings, she was treated for bacterial pneumonia and later pulmonary tuberculosis without any improvement until she arrived at our pulmonology clinic with worsening symptoms.

Diagnostic assessment: a chest X-ray (Figure 1) and CT chest (Figure 2) from a peripheral hospital in early 2021 uncovered a cavitating lesion in the medial basal segment of the right lower lobe. A follow-up CT chest (Figure 3) revealed a cavitating lesion with surrounding ground-glass opacities. She arrived at our hospital in early 2022 due to further clinical deterioration. We did a workup for the infective process in conformity with the radiological pattern and the prevalence of diseases in South Africa. Sputum for GeneXpert, TB culture, cytology, and several blood tests that included full blood count, C-reactive protein, kidney function, autoimmune studies were unremarkable. A further CT chest (Figure 4) showed multiple cavitating lesions in both lung fields. An open lung biopsy was consistent with invasive mucinous adenocarcinoma with a negative epithelial growth factor receptor (EGFR). She subsequently progressed to respiratory failure, with a CT chest (Figure 5) showing bilateral cavitating lesions.

Diagnosis: mucinous adenocarcinoma.

Therapeutic interventions: the patient had died before appropriate treatment was instituted.

Patient perspective: maybe it was meant to be.

Informed consent: written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Discussion     

This case highlights an unusual radiographic presentation of BAC as non-resolving cavitating pneumonia should alert any clinician, even the radiologists [4]. Bronchoalveolar carcinoma (BAC) is a non-small cell lung cancer (NSCLC), accounting for 6.5% of lung malignancies [5]. It is commonly described in younger females between 40 and 70, non-smokers with common cough symptoms, shortness of breath, haemoptysis, and fever [6]. Bronchorrhea is a rare and late manifestation [7]. It has varying radiographic patterns, including solitary lesion, consolidation and a multifocal or diffuse pattern [2]. In our case, the presentation is unusual as it is not of the described radiological patterns of BAC, leading to a delayed diagnosis. One case report by Maskiny et al. described a similar unique presentation of BAC as multifocal bilateral cavitating lesions [8]. The mucinous form of adenocarcinoma is the most aggressive form that responds poorly to treatment [9]. The survival of the majority of patients with lung cancer is poor. The earlier the cancer is diagnosed, the higher the cure rate with surgery. Thus, the starting point of early diagnosis and hence early treatment should be a high index of suspicion in a patient with radiological findings of non-resolving pneumonia. The delay in diagnosis of this rare disease was compounded by fragmented care and poor communication of general practitioners (gatekeepers) who were doing follow-ups for this patient and their seniors.

Conclusion     

To avoid missing their diagnosis, gatekeepers and specialists in Africa should be aware of these rare and difficult-to-recognise conditions such as mucinous adenocarcinoma. Missed diagnosis of cancer leads to significant delay in offering adequate treatment. Dare to think rare!

Competing interests     

The authors declare no competing interests.

Authors' contributions     

All the authors have read and agreed to the final manuscript.

Figures     

Figure 1: chest X-ray (2021): right middle zone ill-defined opacity

Figure 2: CT chest (2021): right middle and lower zone cavitating lesion

Figure 3: CT chest (after 3 months of treatment of cavitating pneumonia): right middle and lower zone cavitating lesion with surrounding ground-glass opacity

Figure 4: CT chest (after 1 year of treatment of cavitating pneumonia): bilateral cavitating lesions

Figure 5: CT chest (upon arrival at our facility): extensive dense consolidation of right hemithorax with multiple cavitating lesions on the left hemithorax

References