Figure 1
Thoracic AP radiograph
Thoracic radiography showing multiple high density micronodular opacities with predominance in both upper lobes, sparing the lowest two thirds of lungs.
Clinical History
A 45-year-old Caucasian female patient with a prior history of chronic renal insufficiency due to medullary sponge kidney, with secondary hyperparathyroidism, was admitted in our institution for serious hypokalaemia and anaemia. The patient had neither smoking history nor signs or symptoms of respiratory disease.
Imaging Findings
A routine chest X-ray showed multiple high density micro-nodular opacities in the upper lobes of the lungs. To better characterize those pulmonary abnormalities, a thoracic CT was requested, depicting diffuse high density nodular opacities consistent with centrilobular calcifications in the upper lobes of the lungs. A non-enhanced abdomino-pelvic CT demonstrated findings of renal pyramid calcifications related to nephrocalcinosis.
Discussion
Diffuse pulmonary calcification, also known as pulmonary metastatic calcification, is a progressive interstitial process, usually related with chronically elevated serum calcium levels, in which calcium is deposited in the alveolar septa, bronchial walls and pulmonary arteriole. [1-6]
Despite being a frequent complication in end-stage chronic renal insufficiency treated with haemodialysis, most patients remain asymptomatic, and a small portion develops severe respiratory symptoms, related to the extent of pulmonary calcification and fibrosis with restrictive syndrome. [2, 5-8]
Conventional chest radiographs lack sensitivity and specificity for this pathology that may simulate pulmonary oedema, airspace disease or appear as diffuse interstitial infiltrates. [4, 8]
The superior sensitivity of high-resolution computed tomography (HRCT) allows the detection of small lung calcifications, which can be associated with vascular calcifications and/or centrilobular ground-glass nodular opacities, with numerous poorly defined nodules measuring 3–10 mm in diameter. [2-5]
An upper lobe predominance for metastatic pulmonary calcification has been reported, supposedly due to higher ventilation-perfusion ratio and increased alkalinity that favours calcium precipitation. [1, 6]
The differential diagnosis includes lung dystrophic calcifications due to a variety of other conditions such as infections (e.g. tuberculosis), silicosis, sarcoidosis, metastatic tumour, rheumatic mitral stenosis, microlithasis and broncholithiasis, each one with different patterns of parenchymal involvement. [3, 4]
It is important to be aware of this entity to correctly identify this potentially progressive and fatal cause of respiratory failure, as appropriate measures can be taken to reverse hypercalcaemia. In addition, recognition of metastatic pulmonary calcification at CT may, in some cases, obviate the need for more invasive procedures, such as open-lung biopsy, to determine the cause of a noncleaning infiltrate in a patient with end-stage renal failure.
Despite being a frequent complication in end-stage chronic renal insufficiency treated with haemodialysis, most patients remain asymptomatic, and a small portion develops severe respiratory symptoms, related to the extent of pulmonary calcification and fibrosis with restrictive syndrome. [2, 5-8]
Conventional chest radiographs lack sensitivity and specificity for this pathology that may simulate pulmonary oedema, airspace disease or appear as diffuse interstitial infiltrates. [4, 8]
The superior sensitivity of high-resolution computed tomography (HRCT) allows the detection of small lung calcifications, which can be associated with vascular calcifications and/or centrilobular ground-glass nodular opacities, with numerous poorly defined nodules measuring 3–10 mm in diameter. [2-5]
An upper lobe predominance for metastatic pulmonary calcification has been reported, supposedly due to higher ventilation-perfusion ratio and increased alkalinity that favours calcium precipitation. [1, 6]
The differential diagnosis includes lung dystrophic calcifications due to a variety of other conditions such as infections (e.g. tuberculosis), silicosis, sarcoidosis, metastatic tumour, rheumatic mitral stenosis, microlithasis and broncholithiasis, each one with different patterns of parenchymal involvement. [3, 4]
It is important to be aware of this entity to correctly identify this potentially progressive and fatal cause of respiratory failure, as appropriate measures can be taken to reverse hypercalcaemia. In addition, recognition of metastatic pulmonary calcification at CT may, in some cases, obviate the need for more invasive procedures, such as open-lung biopsy, to determine the cause of a noncleaning infiltrate in a patient with end-stage renal failure.
Differential Diagnosis List
Diffuse pulmonary calcification in the context of end-stage renal insufficiency
Tuberculosis
Silicosis
Sarcoidosis
Metastatic tumour
Final Diagnosis
Diffuse pulmonary calcification in the context of end-stage renal insufficiency
References
[1] Kang EH, Kim ES, Kim CH, Ham SY, Oh YW (2008) Atypical Radiological Manifestation of Pulmonary Metastatic Calcification. Korean J Radiol 9:186-189 (PMID: 18385568)
[2] Bozi LCF, Melo ASA, Marchiori E (2012) Pulmonary metastatic calcification: a case report. Radiol Bras 45(5):297–299
[3] Castillo MC, Gimeno MJ, Carro B, Benito JL, Freile E, Sainz JM (2005) Diffuse Pulmonary Calcification in a Patient With Renal Insufficiency. Arch Bronconeumol 41(10):587-9 (PMID: 16266674)
[4] Murris-Espin M, Lacassagne L, Didier A, Voigt JJ, Cisterne JM (1997) Metastatic pulmonary calcification after renal transplantation. European Respiratory Journal 10: 1925–1927 (PMID: 9272941)
[5] Hochhegger B, Marchiori E, Sousa Jr AS (2012) MRI and CT findings of metastatic pulmonary calcification. The British Journal of Radiology 85 (2012), e69–e72 (PMID: 22391505)
[6] Rastogi S, Boyars M, Eltorky M, Taneja S (2006) Metastatic Pulmonary Calcification in a Patient With End-Stage Renal Disease on Hemodialysis: A common Complication But a Rare Clinical Diagnosis. Johns Hopkins Advanced Studies in Medicine Vol. 6, No2
[7] Villalobos RS, Becerra ER, Naranjo FB, Juan JM (2003) Calcificación pulmonar metastásica: una rara causa. Arch Bronconeumol 2003;39(4):184-6
[8] Madhusudhan KS, Shad PS, Sharma S, Goel A, Mahajan H (2011) Metastatic Pulmonary Calcification in Chronic Renal Failure. Int Urol Nephrol 44(4):1285-7 (PMID: 21779916)
Case information
| URL: | https://www.eurorad.org/case/12811 |
| DOI: | 10.1594/EURORAD/CASE.12811 |
| ISSN: | 1563-4086 |
License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Figure 3
Abdomino-pelvic CT
Coronal reconstruction of abdomino-pelvic CT, demonstrating high density of the renal medular pyramids, consistent with nephrocalcinosis.
Thoracic AP radiograph
Thoracic radiography showing multiple high density micronodular opacities with predominance in both upper lobes, sparing the lowest two thirds of lungs.
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal.
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal.
Thoracic CT
Axial section of thoracic CT with lung window showing diffuse high density nodular opacities within alveolar spaces.
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal
Coronal reconstruction of thoracic CT in lung window reveals predominance of the nodular high density opacities in the upper lung lobes.
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal
Abdomino-pelvic CT
Coronal reconstruction of abdomino-pelvic CT, demonstrating high density of the renal medular pyramids, consistent with nephrocalcinosis.
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal
Department of Radiology, Hospital Garcia de Orta, Almada, Portugal