Ann Thorac Surg 2009;88:e22-e24. doi:10.1016/j.athoracsur.2009.06.063
© 2009 The Society of Thoracic Surgeons
Case Reports
Pulmonary Alveolar Microlithiasis in a Textile Worker
Elif Ulker Akyildiz, MDa,*,
Ahmet Ursavas, MDb,
Umit Ogur, MDc
a Department of Pathology, Uludag University School of Medicine, Bursa, Turkey
b Department of Pulmonary Medicine, Uludag University School of Medicine, Bursa, Turkey
c Department of Nuclear Medicine, Uludag University School of Medicine, Bursa, Turkey
Accepted for publication June 9, 2009.
* Address correspondence to Dr Akyildiz, Department of Pathology, Uludag University School of Medicine, Gorukle, Bursa, 16384, Turkey (Email: ulker33{at}yahoo.com).
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Abstract
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Pulmonary alveolar microlithiasis is a rare lung disease characterized by small calculi, called calsispheritis, in the alveoli. The disease usually presents at age 20 to 30 years and is mostly diagnosed incidentally or detected on routine pulmonary roentgenograms. The radiologic findings are pathognomonic for the disease. Pulmonary alveolar microlithiasis most frequently appears in Turkey, followed by Italy. We present the case of a 29-year-old female textile worker found to have widespread micronodules after a routine pulmonary roentgenogram.
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Introduction
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Pulmonary alveolar microlithiasis (PAM) is a rare lung disease characterized by small calculi called calsispheritis in the alveoli. The disease usually presents at age 20 to 30 years and is mostly diagnosed incidentally or detected on routine pulmonary radiographs [1].
Although the etiology of PAM remains unclear, it has been shown not to be a calcium metabolism disorder. Sporadic and familial cases are reported. It is noteworthy that family members with PAM generally live in the same environment. A few studies of PAM have implicated environmental factors; however, none of the environmental agents have been confirmed [2–5]. In this report, we present a patient with radiologic and pathologic features of PAM.
A 29-year-old female textile worker was found to have widespread micronodules on a routine pulmonary radiograph (Fig 1), marked especially in the lower pulmonary fields. The patient did not have any complaints. High-resolution computed tomography (HRCT) imaging showed increased, widespread reticulonodular interstitial density in the lungs, especially marked at the bases (Fig 2). For this reason, a thoracoscopic biopsy was performed that revealed interstitial lung disease.
The patient was referred to our hospital for further investigations and treatment. During the physical examination, we did not detect any abnormality except for crepitant rales on auscultation. A bronchoscopy showed no major pathology, and bronchoalveolar lavage did not reveal any abnormality.
Paraffin-embedded tissues were reexamined in the pathology department of our hospital. Histopathologic examination revealed calcified bodies in the alveoli characterized by concentric lamination, different diameters, and irregular circumferences in some (Fig 3). There was no chronic inflammation or fibrosis in the interalveolar septa. The patient was diagnosed as having PAM from these histopathologic findings. This diagnosis was confirmed by pulmonary scintigraphy using technetium 99m-metilen diphosphonate (Tc99m-MDP). Tc99m-MDP enhancement was observed in the middle and lower zones of the lungs.
All of the patient's family members were examined, and pulmonary roentgenograms were taken; however, none displayed signs of PAM.
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Comment
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PAM is a rare disease first described by Harbitz in 1918 [6]. It is characterized by stones in the alveolar lumens composed of calcium or phosphate, or both, called calcispheritis or microlith. The disease most frequently appears in Turkey, followed by Italy and the United States [1, 7]. The disease typically presents in the third to fourth decades of life; however, pediatric and elderly patients with PAM have also been reported [1, 8]. Although the disease can be sporadic, one-third of all patients have a family history of PAM [1, 9].
At present, the etiology and pathogenesis of PAM is not known. A preponderance of men in sporadic PAM and of women in familial PAM has been reported. The reason for the preponderance for men in Turkey may be that the disease is recognized on routine pulmonary roentgenograms taken before military service [7]. However, the patient here is a female textile worker, and the disease was diagnosed on a health screening.
More than half of all patients with PAM do not display symptoms of the disease at the time of diagnosis [10]. The indolent clinical course of PAM contradicts with the radiologic findings that are pathognomonic for the disease. There are diffuse micronodular calcifications in the lungs, especially marked in the lower zones, described as a sand storm. HRCT shows a ground glass appearance, interlobular septal thickening, and peribronchovascular and subpleural interstitial thickening. Bone scintigraphy reveals intense lung uptake of Tc99m [1].
The clinical course of PAM varies. Although the disease does not show any progression in some patients, interstitial fibrosis or cor pulmonale may occur in others. No specific therapy has yet been reported. Pulmonary lavage has been tried, with no considerable benefits, and disodium ethydronate, a drug that inhibits hydroxyapatite metabolism, has achieved minimal benefits. Lung transplantation is yet another treatment that may be used in PAM cases [11].
Histopathologic examination of specimens from our patient revealed concentric calcified bodies in the alveoli and interstitium. These structures may also occur in the bronchial submucosa. Ossification in the peripheries of calcispheritis may sometimes be observed in old lesions. Microlith may also be detected in sputum and bronchioalveolar lavage specimens. The differential diagnosis of PAM includes pulmonary calcification, corpora amylacea, and blue bodies.
As mentioned, the etiology and pathogenesis of PAM is still not clear. Some have claimed it is not to be an autosomal recessive disease, and that its frequency among the members of the same family may be due to living in the same environment. To date, however, no substance or pathogen has been incriminated for PAM. Mikhailov [2] reported 4 patients with PAM living on the same farm, 3 of whom were relatives [2]. Chinachoti and Tangchai [3] reported 9 patients with PAM who inhaled a kind of tobacco containing calcium. Esquerra-Gomez [4] reported 4 sisters with PAM and showed that 3 other sisters, who were sent away when they were young, did not have the disease. A PAM patient who was exposed to press ink for 9 months has also been reported [5].
Considering that PAM may be due to environmental factors, people sharing the same environment with patients should be screened, as well as family members of those with the disease. Examination of family members and others close to the patient helps to make an early diagnosis of PAM. We performed radiologic examinations on the patient's family members and health screening on her colleagues at the workplace, but none appeared to have PAM. We believe that more research is needed to find a parallel between textile materials and the etiology of the disease.
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References
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- Mikhailov V. Pulmonary alveolar microlithiasis Klin Med 1954;32:31-36.
- Chinachoti N, Tangchai P. Pulmonary alveolar microlithiasis associated with inhalation of snuff in Thailand Dis Chest 1957;32:687-689.[Medline]
- Esguerra-Gomez G, Lichtemberger E, Santamaria A, et al. Familial pulmonary alveolar microlithiasis: four cases from Colombia Radiology 1959;72:550-561.[Medline]
- Prakash UB, Barham SS, Rosenow 3rd EC, Brown ML, Payne WS. Pulmonary alveolar microlithiasis. A review including ultrastructural and pulmonary function studies. Mayo Clin Proc 1983;58:290-300.[Medline]
- Harbitz F. Extensive calcification of the lungs as a distinct disease Arch Intern Med 1918;21:139-146.
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- Göcmen A, Toppare MF, Kiper N, Büyükpamukcu N. Treatment of pulmonary alveolar microlithiasis with a diphosphonate—preliminary results of a case Respiration 1992;59:250-252.[Medline]
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Abstract
Introduction
