Pulmonary sarcoidosis: morphologic associations of airflow obstruction at thin-section CT

PURPOSE: To identify relationships between the obstructive defects of pulmonary sarcoidosis and the computed tomographic (CT) patterns of disease. MATERIAL AND METHODS: CT scans obtained in 45 patients were scored semiquantitatively for extent of five CT patterns, and the functional importance of each pattern was evaluated. RESULTS: The most prevalent CT patterns were decreased attenuation (n = 40), a reticular pattern (n = 37), and a nodular pattern (n = 36). At univariate and multivariate analyses, a reticular pattern was the main determinant of functional impairment, particularly airflow obstruction. The extent of a reticular pattern was independently associated with airflow obstruction, as shown by the inverse relationships with the forced expiratory volume in 1 second (FEV1) (P < .001), FEV1-forced vital capacity ratio (P < .01), maximum expiratory flow at 25% above residual volume (P < .001), and maximum expiratory flow at 50% above residual volume (P < .001) and the positive relationship with the residual volume-total lung capacity ratio (P < .001). CONCLUSION: In sarcoidosis, CT features compatible with small airways disease are common but contribute little to airflow obstruction, particularly in more advanced disease, which is characterized by an extensive reticular pattern. A reticular pattern at CT is the major morphologic association of airflow obstruction.     

Extrapulmonary sarcoidosis

The clinical manifestations of sarcoidosis are extremely heterogeneous and overlap with a wide gamut of infectious and noninfectious granulomatous disorders. Prognosis of sarcoidosis is highly variable. Spontaneous remissions occur in nearly two thirds of patients, but chronic, progressive disease may result in severe sequelae. Fatalities occur in 1% to 4% of patients. Pulmonary manifestations typically dominate, but any organ can be affected. Skin, eye, and peripheral lymph nodes are each involved in 20% to 30% of patients. Clinically significant involvement of spleen, liver, bone, heart, kidney, or central nervous system occurs in 2% to 6% of patients. Asymptomatic involvement of these organs is far more common. We review the salient extrapulmonary features of sarcoidosis, and compare and contrast specific features that may mimic other etiologies.     

Muscular sarcoidosis

A 57-year-old woman with sarcoid nodules in muscles of the lower leg was reported. A star-shaped low signal intensity in the lesion on MR imaging, supposedly corresponding to fibrous scar, appears characteristic of this condition, although its specificity is still uncertain.     

Genetics of sarcoidosis

Hereditary susceptibility to sarcoidosis is suggested by ethnic preponderance, familial clustering, and multigenerational involvement. The genetics of sarcoidosis cannot be adequately addressed in small samples of patients; a large-scale study with stratification for patient phenotypic differences is necessary. A study that uses both genetic marker and environmental data would be able to control for and examine different causative mechanisms. Until such a well-designed, comprehensive study is carried out, we are left with interesting patterns of disease in families and uncertain allelic associations.     

Treatment of sarcoidosis

We report the effect of the 11,778 and 3460 base pair mitochondrial DNA mutations, found in Leber's hereditary optic neuropathy (LHON), on platelet mitochondrial respiratory chain enzyme activity. We measured respiratory chain enzyme activities in platelets from 4 patients with the 3460 mutation, 17 patients with the 11,778 mutation and compared them with those of 41 healthy age-matched controls. We observed a 67% (P < 0.001) reduction in the mean NADH CoQ1 reductase (complex I) activity of the 3460 group compared to the control group. It has been shown previously that platelet mitochondrial biochemistry is affected by cigarette smoking. A significant reduction (25%, P < 0.03) in the mean complex I activity of the 11,778 group was only observed when the non-smokers within that group were compared to the non-smoking controls. The effect of smoking observed in this study may explain why previous workers have not observed a decrease in complex I activity associated with the 11,778 mutation. There was no significant change in the activity of complexes II/III or IV with either of these mutations. There was a significant increase (26%, P < 0.008) in citrate synthase (CS) activity with the non-smoking 11,778 group compared to the non-smoking control group, rising to 40% (P < 0.002) in those with this mutation who smoked. This reflects an increase in mitochondrial mass with the 11,778 mutation. This effect was not observed with the 3460 mutation even though the complex deficiency was much more severe.     

Hypoparathyroidism and sarcoidosis

Tension pneumoperitoneum is a known although rare complication of barotrauma, which can accompany blast injury. We report two patients who suffered from severe pulmonary blast injury, accompanied by tension pneumoperitoneum, and who were severely hypoxemic, hypercarbic, and in shock. After surgical decompression of their pneumoperitoneum, respiratory and hemodynamic functions improved dramatically. Several mechanisms to explain this improvement are suggested. In such cases the release of the tension pneumoperitoneum is mandatory, and laparotomy with delayed closure can be contemplated.     

Etiology of sarcoidosis

Since sarcoidosis was first recognized as a distinct clinical entity, investigators have speculated that a transmissible agent may cause sarcoidosis. Recent attempts at directly isolating infectious organisms or indirectly detecting microbial DNA or RNA from sarcoid tissue have led to inconclusive results. Studies on the immunopathogenic origins of sarcoidosis have provided evidence of persistent antigenic stimulation at sites of inflammation that are associated with dysregulated cytokine production. To date, however, the challenge of defining the cause of sarcoidosis remains unmet.     

Imaging of pulmonary sarcoidosis

Imaging plays a fundamental role in every step of the management of thoracic sarcoidosis. It contributes to the positive and differential diagnosis and assessment of the prognosis. It is able to distinguish between inflammatory lesions and fibrosis. It allows follow-up of the course of the disease with or without treatment and detection of any complications. Computed tomography provides very useful complementary information at each of these steps.     

Oral manifestations of sarcoidosis

OBJECTIVE: To report two new cases of sarcoidosis of the buccal mucosa and to analyze the literature on oral manifestations of sarcoidosis. STUDY DESIGN: Oral lesions with histologic features of sarcoidosis were analyzed according to their location and appearance. RESULTS: Analysis of 45 cases of oral sarcoidosis (43 from the literature and the 2 new presented cases) revealed 12 lesions in the jaws, 10 in the buccal mucosa, 6 in the gingiva, 5 in the lips, 5 in the floor of the mouth, 4 in the tongue, and 3 in the palate. Sarcoidosis in the jaw was located in the alveolar bone and presented as an ill-defined radiolucency. Submucosal nodules were observed in sarcoidosis affecting the buccal mucosa, palate, and lip. Swelling was the main manifestation in the gingiva. In the floor of the mouth, sarcoidosis presented as ranula and that of the tongue as induration. In most of the cases, the lesions in the buccal mucosa, gingiva, and tongue were the first clinical manifestation of the disease. CONCLUSION: Oral sarcoidosis lesions should be considered in the differential diagnosis of oral soft tissue swellings and jaw lesions.     

Vertebral sarcoidosis in adolescents

Two cases of vertebral sarcoidosis in pediatric patients are presented. All such patients reported have been black, 13-15 years old, and have a history of back pain. Radiographs of the involved vertebrae show primarily lytic destruction with sclerotic borders in some of the lesions. Fungal infections, tuberculosis, pyogenic osteomyelitis, Hodgkin's disease and metastatic disease must be considered in every patient with vertebral sarcoidosis.