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Department of Radiology
Seth G.S. Medical College and K.E.M. Hospital, Mumbai , India
Case of the Month
Case of the Month
One Disease or Many?
One Disease or Many?
Occam’s Razor vs Hickam’s Dictum in a case of Metastatic Adenocarcinoma of lung with Multisystem Infective Mimics
Occam’s Razor vs Hickam’s Dictum in a case of Metastatic Adenocarcinoma of lung with Multisystem Infective Mimics
Contributed by : Swathi Saralaya
Contributed by : Swathi Saralaya
Occam’s Razor is named after William of Ockham (c. 1287–1347), a 14th-century English scholastic philosopher, and theologian. Hickam’s Dictum is named after Dr. John Bamber Hickam (1914–1970), an American physician who was the chair of the Department of Medicine at Indiana University.
Introduction :
Introduction :
Lung cancer is a leading cause of cancer related mortality with adenocarcinoma being the most common subtype, particularly in non-smokers and younger patients. It frequently metastasizes early, with the brain being a common site, and may occasionally present initially with neurological manifestations.
Lung cancer is a leading cause of cancer related mortality with adenocarcinoma being the most common subtype, particularly in non-smokers and younger patients. It frequently metastasizes early, with the brain being a common site, and may occasionally present initially with neurological manifestations.
Brain metastases typically appear as ring-enhancing lesions with surrounding edema on imaging, closely mimicking infective conditions such as tuberculosis, neurocysticercosis, and fungal infections, especially in endemic regions. This overlap often creates diagnostic uncertainty and may delay appropriate management.
Brain metastases typically appear as ring-enhancing lesions with surrounding edema on imaging, closely mimicking infective conditions such as tuberculosis, neurocysticercosis, and fungal infections, especially in endemic regions. This overlap often creates diagnostic uncertainty and may delay appropriate management.
Although advanced imaging techniques can aid in differentiation, they are not always conclusive, and histopathological confirmation is often necessary. This case underscores the importance of maintaining a high index of suspicion in atypical presentations.
Although advanced imaging techniques can aid in differentiation, they are not always conclusive, and histopathological confirmation is often necessary. This case underscores the importance of maintaining a high index of suspicion in atypical presentations.
Case presentation :
Case presentation :
A 59 year old man, came with complaints of recurrent episodes of seizures in November 2025, He underwent series of investigations and MRI of the brain however he was discharged against medical advice in December 2025 and then two months later he presented with complaints of severe breathlessness and cough. He also gave history of significant weight loss over the last few months.
A 59 year old man, came with complaints of recurrent episodes of seizures in November 2025, He underwent series of investigations and MRI of the brain however he was discharged against medical advice in December 2025 and then two months later he presented with complaints of severe breathlessness and cough. He also gave history of significant weight loss over the last few months.
He was a known case of ischemic heart disease with EF 30%, Chronic smoker and alcoholic for more than 30 years duration.
He was a known case of ischemic heart disease with EF 30%, Chronic smoker and alcoholic for more than 30 years duration.
He was found to have gross pleural effusion on chest radiograph, The pleuritic fluid was tapped and ICD was inserted. The sample was sent for analysis and was found to have ADA (adenosine deaminase) levels within normal limits in the pleuritic fluid sample. He was then advised CECT of the chest and brain for further evaluation and his previous imaging was also reviewed.
He was found to have gross pleural effusion on chest radiograph, The pleuritic fluid was tapped and ICD was inserted. The sample was sent for analysis and was found to have ADA (adenosine deaminase) levels within normal limits in the pleuritic fluid sample. He was then advised CECT of the chest and brain for further evaluation and his previous imaging was also reviewed.
Radiological findings:
Radiological findings:
On MRI of the brain with orbit (December 2025). There are multiple variable sized ring enhancing lesions seen throughout the cerebral parenchyma bilaterally, both the thalamus, left lentiform nucleus, right hippocampus, both cerebellar hemispheres. Few of them show mild perilesional edema, largest measuring 15x13mm in the left high parietal lobe showing small focus of blooming within. The lesions show no diffusion restriction.(Figure 1A and 1B)
On MRI of the brain with orbit (December 2025). There are multiple variable sized ring enhancing lesions seen throughout the cerebral parenchyma bilaterally, both the thalamus, left lentiform nucleus, right hippocampus, both cerebellar hemispheres. Few of them show mild perilesional edema, largest measuring 15x13mm in the left high parietal lobe showing small focus of blooming within. The lesions show no diffusion restriction.(Figure 1A and 1B)
Fig 1
On MRI of the brain with orbit Figure 1A and 1B: There are multiple variable sized ring enhancing lesions (white arrows) seen throughout the cerebral parenchyma bilaterally, both the thalamus, left lentiform nucleus, right hippocampus, both cerebellar hemispheres. Few of them show mild perilesional edema, largest measuring 15x13mm in the left high parietal lobe showing small focus of blooming within. The lesions show no diffusion restriction.
There is an ill-defined heterogeneously T2 iso-hyperintense, T1 iso intense soft tissue lesion in left orbit predominantly involving the retrobulbar region encasing the orbital and canalicular segment of left optic nerve and all extra ocular muscles with effaced fat planes. It is extending into the orbital apex and minimally into left cavernous sinus, which however shows normal contrast opacification. However bilateral cavernous ICAs show normal flow void. It shows diffusion restriction and extensive post contrast enhancement. No obvious proptosis seen on left. The left lacrimal gland appears bulky. There is meningeal thickening in left basifrontal region with adjacent edema in the brain parenchyma. (Figure 2A and 2B) These imaging features are most suggestive of disseminated metastatic deposits, however tuberculomas/NCC can present similarly.
There is an ill-defined heterogeneously T2 iso-hyperintense, T1 iso intense soft tissue lesion in left orbit predominantly involving the retrobulbar region encasing the orbital and canalicular segment of left optic nerve and all extra ocular muscles with effaced fat planes. It is extending into the orbital apex and minimally into left cavernous sinus, which however shows normal contrast opacification. However bilateral cavernous ICAs show normal flow void. It shows diffusion restriction and extensive post contrast enhancement. No obvious proptosis seen on left. The left lacrimal gland appears bulky. There is meningeal thickening in left basifrontal region with adjacent edema in the brain parenchyma. (Figure 2A and 2B) These imaging features are most suggestive of disseminated metastatic deposits, however tuberculomas/NCC can present similarly.
Fig 2
Figure 2A and 2B: There is an ill-defined heterogeneously T2 iso-hyperintense, T1 iso intense soft tissue lesion (white arrows) in left orbit predominantly involving the retrobulbar region encasing the orbital and canalicular segment of left optic nerve and all extra ocular muscles with effaced fat planes. It is extending into the orbital apex and minimally into left cavernous sinus, which however shows normal contrast opacification. However bilateral cavernous ICAs show normal flow void. It shows diffusion restriction and extensive post contrast enhancement. There is meningeal thickening in left basifrontal region with adjacent edema in the brain parenchyma.
On Frontal chest radiographs (February 2026). There is complete opacification of the left hemithorax (Figure 3A) There is shift of trachea towards right Post ICD insertion
On Frontal chest radiographs (February 2026). There is complete opacification of the left hemithorax (Figure 3A) There is shift of trachea towards right Post ICD insertion
There is resolution of opacity in left hemithorax (Figure3B) Left hydropneumothorax seen.Left anterior chest wall and axillary subcutaneous emphysema seen.
There is resolution of opacity in left hemithorax (Figure3B) Left hydropneumothorax seen.Left anterior chest wall and axillary subcutaneous emphysema seen.
Figure 3
On Frontal chest radiographs Figure 3A: There is complete opacification of the left hemithorax (white arrow) There is shift of trachea towards right Figure3B: Post ICD insertion There is resolution of opacity in left hemithorax Left hydropneumothorax seen. Left anterior chest wall and axillary subcutaneous emphysema seen. On CECT Brain and Chest,
On CECT Chest, (February 2026), There is an ill-defined heterogeneously enhancing spiculated cavitating lesion measuring 2.6cmx2.9cm at the level of division of the left lower lobe bronchus with cutoff of the anterior medial and lateral segment bronchiole (Figure 4A and 4B). These findings are highly suggestive of a primary bronchogenic malignancy. There is gross left hydropneumothorax with ICD in situ with its tip abutting the left apical pleura and left lung volume loss
On CECT Chest, (February 2026), There is an ill-defined heterogeneously enhancing spiculated cavitating lesion measuring 2.6cmx2.9cm at the level of division of the left lower lobe bronchus with cutoff of the anterior medial and lateral segment bronchiole (Figure 4A and 4B). These findings are highly suggestive of a primary bronchogenic malignancy. There is gross left hydropneumothorax with ICD in situ with its tip abutting the left apical pleura and left lung volume loss
The left adrenal is bulky and peripherally enhancing with maintained contour (Figure 5).This feature was suggestive of granulomatous adrenalitis. However early metastases also present with an enlarged gland with maintained contour.
The left adrenal is bulky and peripherally enhancing with maintained contour (Figure 5).This feature was suggestive of granulomatous adrenalitis. However early metastases also present with an enlarged gland with maintained contour.
Figure 4
On CECT Brain and Chest, Figure 4A and 4B: There is an ill-defined heterogeneously enhancing spiculated cavitating lesion (white arrows) measuring 2.6cmx2.9cm at the level of division of the left lower lobe bronchus with cutoff of the anterior medial and lateral segment bronchiole There is gross left hydropneumothorax with ICD in situ with its tip abutting the left apical pleura and left lung volume loss
Figure 5
The left adrenal(red arrow) is of normal contour; is bulky and enhances peripherally
There are multiple sub centimetric sized calcific foci scattered throughout the cerebral parenchyma and deep nuclei some of these show peripheral enhancement without significant vasogenic edema or mass effect. However there are few ring enhancing lesions in right temporal lobe and left parietal lobe with mild vasogenic edema in the subcortical white matter adjacent to the latter.(Figure 6A and 6B) . There is an iso-dense peripherally enhancing lesion in the left orbit extending from retrobulbar region to the orbital apex involving the extraconal, conal and intraconal compartment. The optic nerve is passing through this lesion. There is bulging of left lateral wall of left cavernous sinus. There is rarefaction of left lamina papyracea and posterolateral wall of left orbit. (Figure 6C).
There are multiple sub centimetric sized calcific foci scattered throughout the cerebral parenchyma and deep nuclei some of these show peripheral enhancement without significant vasogenic edema or mass effect. However there are few ring enhancing lesions in right temporal lobe and left parietal lobe with mild vasogenic edema in the subcortical white matter adjacent to the latter.(Figure 6A and 6B) . There is an iso-dense peripherally enhancing lesion in the left orbit extending from retrobulbar region to the orbital apex involving the extraconal, conal and intraconal compartment. The optic nerve is passing through this lesion. There is bulging of left lateral wall of left cavernous sinus. There is rarefaction of left lamina papyracea and posterolateral wall of left orbit. (Figure 6C).
The left orbital apex lesion was likely infective >neoplastic origin. Numerous calcified enhancing lesions of the brain were also suggestive of infective>neoplastic origin.
The left orbital apex lesion was likely infective >neoplastic origin. Numerous calcified enhancing lesions of the brain were also suggestive of infective>neoplastic origin.
Figure 6 A, B C
Figure 6A and 6B: There are multiple subcentimetric sized calcific foci(white arrows) scattered throughout the cerebral parenchyma and deep nuclei some of these show peripheral enhancement without significant vasogenic edema or mass effect. However there are few ring enhancing lesions in right temporal lobe and left parietal lobe with mild vasogenic edema in the subcortical white matter adjacent to the latter.
Figure 6C: There is an iso-dense peripherally enhancing lesion(red arrow) in the left orbit extending from retrobulbar region to the orbital apex involving the extraconal, conal and intraconal compartment. The optic nerve is passing through this lesion. There is bulging of left lateral wall of left cavernous sinus. There is rarefaction o left lamina papyracea and posterolateral wall of left orbit.
Timeline
Timeline
Radiological diagnosis:
Radiological diagnosis:
Metastatic adenocarcinoma of lung was diagnosed by histopathological confirmation through biopsy of necrotic cervical lymph nodes.
Metastatic adenocarcinoma of lung was diagnosed by histopathological confirmation through biopsy of necrotic cervical lymph nodes.
Management:
Management:
The patient was referred to a specialised cancer treatment centre and was given palliative care
The patient was referred to a specialised cancer treatment centre and was given palliative care
Discussion
Discussion
This case highlights the enduring clinical tension between diagnostic parsimony and plurality—embodied by Occam’s razor and Hickam’s dictum—in the evaluation of multisystem disease (1,2). At presentation, seizures with multiple ring-enhancing intracranial lesions strongly favored infective etiologies such as neurocysticercosis or tuberculoma, particularly in an endemic setting (3,4). Associated findings, including bulky adrenal glands and an orbital lesion, appeared to support a unifying granulomatous process, reinforcing an Occam-driven approach.
This case highlights the enduring clinical tension between diagnostic parsimony and plurality—embodied by Occam’s razor and Hickam’s dictum—in the evaluation of multisystem disease (1,2). At presentation, seizures with multiple ring-enhancing intracranial lesions strongly favored infective etiologies such as neurocysticercosis or tuberculoma, particularly in an endemic setting (3,4). Associated findings, including bulky adrenal glands and an orbital lesion, appeared to support a unifying granulomatous process, reinforcing an Occam-driven approach.
However, thoracic imaging findings were discordant. A spiculated hilar mass with bronchial cutoff, mediastinal lymphadenopathy, and randomly distributed pulmonary nodules were more suggestive of a primary lung malignancy with metastases (5). Histopathological confirmation of lung adenocarcinoma ultimately unified the multisystem involvement under a single neoplastic etiology.
However, thoracic imaging findings were discordant. A spiculated hilar mass with bronchial cutoff, mediastinal lymphadenopathy, and randomly distributed pulmonary nodules were more suggestive of a primary lung malignancy with metastases (5). Histopathological confirmation of lung adenocarcinoma ultimately unified the multisystem involvement under a single neoplastic etiology.
A key challenge in this case is the significant radiological overlap between metastatic disease and infective granulomas. Brain metastases may present as ring-enhancing lesions with necrosis and surrounding edema, closely mimicking infectious processes (6–10). Similarly, adrenal and orbital metastases can simulate granulomatous disease (11). In such scenarios, imaging alone lacks specificity, and overreliance on endemic prevalence may delay accurate diagnosis.
A key challenge in this case is the significant radiological overlap between metastatic disease and infective granulomas. Brain metastases may present as ring-enhancing lesions with necrosis and surrounding edema, closely mimicking infectious processes (6–10). Similarly, adrenal and orbital metastases can simulate granulomatous disease (11). In such scenarios, imaging alone lacks specificity, and overreliance on endemic prevalence may delay accurate diagnosis.
Conclusion:
Conclusion:
This case highlights the limitations of relying solely on imaging patterns in multisystem disease, particularly in endemic settings where infective etiologies are common mimics. When findings are discordant or span multiple organ systems, a flexible diagnostic approach that balances parsimony with plurality is essential. Early tissue diagnosis remains the cornerstone for resolving ambiguity and ensuring timely identification of potentially treatable malignancies.
This case highlights the limitations of relying solely on imaging patterns in multisystem disease, particularly in endemic settings where infective etiologies are common mimics. When findings are discordant or span multiple organ systems, a flexible diagnostic approach that balances parsimony with plurality is essential. Early tissue diagnosis remains the cornerstone for resolving ambiguity and ensuring timely identification of potentially treatable malignancies.
References:
References:
1. Sackett DL. The arrogance of preventive medicine. CMAJ. 2002;167(4):363–364.
1. Sackett DL. The arrogance of preventive medicine. CMAJ. 2002;167(4):363–364.
2. Hickam JB. A clinical lesson on Occam’s razor. In: Hickam’s Dictum Revisited. 1950s clinical teaching archives; p. 1–3.
2. Hickam JB. A clinical lesson on Occam’s razor. In: Hickam’s Dictum Revisited. 1950s clinical teaching archives; p. 1–3.
3. Neurocysticercosis. Garcia HH, Del Brutto OH. Neurocysticercosis: updated concepts about an old disease. Lancet Neurol. 2005;4(10):653–661.
3. Neurocysticercosis. Garcia HH, Del Brutto OH. Neurocysticercosis: updated concepts about an old disease. Lancet Neurol. 2005;4(10):653–661.
4. Tuberculoma. Rock RB, Olin M, Baker CA, Molitor TW, Peterson PK. Central nervous system tuberculosis: pathogenesis and clinical aspects. Clin Microbiol Rev. 2008;21(2):243–261.
4. Tuberculoma. Rock RB, Olin M, Baker CA, Molitor TW, Peterson PK. Central nervous system tuberculosis: pathogenesis and clinical aspects. Clin Microbiol Rev. 2008;21(2):243–261.
5. Lung adenocarcinoma. Travis WD, Brambilla E, Noguchi M, et al. International association for the study of lung cancer/ATS/ERS classification of lung adenocarcinoma. J Thorac Oncol. 2011;6(2):244–285.
5. Lung adenocarcinoma. Travis WD, Brambilla E, Noguchi M, et al. International association for the study of lung cancer/ATS/ERS classification of lung adenocarcinoma. J Thorac Oncol. 2011;6(2):244–285.
6. Osborn AG. Diagnostic Imaging: Brain. 3rd ed. Salt Lake City: Amirsys; 2016. p. 120–145.
6. Osborn AG. Diagnostic Imaging: Brain. 3rd ed. Salt Lake City: Amirsys; 2016. p. 120–145.
7. Smirniotopoulos JG, Murphy FM, Rushing EJ, Rees JH, Schroeder JW. Patterns of contrast enhancement in the brain and meninges. Radiographics. 2007;27(2):525–551.
7. Smirniotopoulos JG, Murphy FM, Rushing EJ, Rees JH, Schroeder JW. Patterns of contrast enhancement in the brain and meninges. Radiographics. 2007;27(2):525–551.
8. Nayak L, Lee EQ, Wen PY. Epidemiology of brain metastases. Curr Oncol Rep. 2012;14(1):48–54.
8. Nayak L, Lee EQ, Wen PY. Epidemiology of brain metastases. Curr Oncol Rep. 2012;14(1):48–54.
9. Zhang J, Liu Q, Wang J, et al. Imaging features of brain metastases from lung
9. Zhang J, Liu Q, Wang J, et al. Imaging features of brain metastases from lung
adenocarcinoma. Neuroradiology. 2014;56(7):567–576.
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10. Erdogan H, Arslan H, Sakarya ME, et al. Imaging features of intracranial tuberculomas. Clin Imaging. 2005;29(5):306–312.
10. Erdogan H, Arslan H, Sakarya ME, et al. Imaging features of intracranial tuberculomas. Clin Imaging. 2005;29(5):306–312.
11. Lam KY, Lo CY. Metastatic tumours of the adrenal glands: a 30-year experience. Clin Endocrinol (Oxf). 2002;56(1):95–101.
11. Lam KY, Lo CY. Metastatic tumours of the adrenal glands: a 30-year experience. Clin Endocrinol (Oxf). 2002;56(1):95–101.
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