18F-FDG PET/CT characteristics of pulmonary sclerosing hemangioma vs. pulmonary hamartoma

Central and peripheral pulmonary sclerosing pneumocytomas: multi-phase CT study and comparison with Ki-67

BACKGROUND

This study aimed to evaluate the multi-phase CT findings of central and peripheral pulmonary sclerosing pneumocytomas (PSPs) and compared them with Ki-67 to reveal their neoplastic nature.

PATIENTS AND METHODS

Multi-phase CT and clinical data of 33 PSPs (15 central PSPs and 18 peripheral PSPs) were retrospectively analyzed and compared their multi-phase CT features and Ki-67 levels.

RESULTS

For quantitative indicators, central PSPs were larger than peripheral PSPs (10.39 ± 3.25 cm3 vs. 4.65 ± 2.61 cm3, P = 0.013), and tumor size was negatively correlated with acceleration index (r = -0.845, P < 0.001). The peak enhancement of central PSPs appeared in the delayed phase, with a longer time to peak enhancement (TTP, 100.81 ± 19.01 s), lower acceleration index (0.63 ± 0.17), progressive enhancement, and higher Ki-67 level. The peak enhancement of peripheral PSPs appeared in the venous phase, with the shorter TTP (62.67 ± 20.96 s, P < 0.001), higher acceleration index (0.99 ± 0.25, P < 0.001), enhancement washout, and lower Ki-67 level. For qualitative indicators, the overlying vessel sign (86.67% vs. 44.44%, P = 0.027), prominent pulmonary artery sign (73.33% vs. 27.78%, P = 0.015), and obstructive inflammation/atelectasis (26.67% vs. 0%, P = 0.033) were more common in central PSPs, while peripheral PSPs were more common with halo sign (38.89% vs. 6.67%, P = 0.046).

CONCLUSIONS

The location of PSP is a possible contributing factor to its diverse imaging-pathological findings. The tumor size, multi-phase enhancement, qualitative signs, and Ki-67 were different between central and peripheral PSPs. Combined tumor size, multi-phase findings, and Ki-67 level are helpful to reveal the nature of the borderline tumor.

A case of pulmonary sclerosing pneumocytoma diagnosed preoperatively using transbronchial cryobiopsy

Background

The preoperative diagnosis of pulmonary sclerosing pneumocytoma (PSP) is complicated since PSP has several histological structural patterns in the same neoplasm; hence, it is sometimes pathologically misdiagnosed as adenocarcinoma or carcinoid. In recent years, with the prevalence of transbronchial cryobiopsy (TBLC), we are able to obtain larger specimens than previously. However, to date, there have been no reports describing PSP diagnosed using TBLC.

Case reports

A 43-year-old man was referred to our hospital for an abnormal lesion in the left lung discovered on routine health examination. A computed tomography scan of the chest revealed a 14-mm heterogeneous round nodule with surrounding ground-glass opacity in the left lower lobe. The tumor size increased to 18 mm in three weeks, and he developed bloody sputum. TBLC was performed using radial endobronchial ultrasonography and fluoroscopy. An occlusion balloon and prophylactic epinephrine were used to prevent severe bleeding. Histologically, epithelioid cells with solid proliferation, various papillary lesions, and hemosiderin-laden histiocytes were observed. Immunohistochemical staining revealed the histiocytes positive for thyroid transcription factor-1 and vimentin, and the type II pneumocyte-like-cells positive for cytokeratin 7. The tumor was preoperatively diagnosed as a PSP; the patient underwent left basal segmentectomy and consequently, a final diagnosed of PSP was formulated.

Conclusion

We report the first case of PSP preoperatively diagnosed using TBLC. Therefore, cryobiopsy could be beneficial in the preoperative diagnosis of PSP.

Contribution of 18F-FDG PET/CT in the Differential Diagnosis of Pulmonary Hamartomas and Pulmonary Carcinoids

Objectives:

This study aimed to evaluate ¹⁸fluorine-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) findings in the differential diagnosis of pulmonary carcinoids and pulmonary hamartomas.

Methods:

¹⁸F-FDG PET/CT findings of 34 patients with pulmonary carcinoids (12 atypical, 22 typical) and 32 patients with pulmonary hamartomas were retrospectively evaluated. Both mean diameter and mean maximum standardized uptake value (SUV_max) of hamartomas and carcinoids were compared by Mann-Whitney U and Kruskall-Wallis H tests.

Results:

The mean longest diameter of atypical carcinoids (3.5±1.7 cm) was higher than that of hamartomas (2.1±1 cm) (p=0.038). No significant difference was found between the mean diameter of typical carcinoids and mean diameter of hamartomas (p=0.128). The mean SUV_max of atypical carcinoids (5.97±3.7) and typical carcinoids (4.22±1.7) were higher than those of hamartomas (1.65±0.9) (p=0.002 and p=0.003, respectively). There were collapse/consolidation in 55.8%, bronchiectasis or mucoid impaction in 47%, and air trapping in 14.7% in the peripheral parenchyma of the 34 carcinoids. Collapse/consolidation was detected in a patient with endobronchial hamartoma, and other finding was not found in the parenchyma around hamartomas.

Conclusion:

The ¹⁸F-FDG uptake of pulmonary carcinoids can vary from minimal to intense. ¹⁸F-FDG uptake can be seen in pulmonary hamartomas. However, the mean SUV_max of atypical carcinoids and typical carcinoids were higher compared to hamartomas. Pulmonary carcinoid must be suspected in cases with accompanying bronchial obstruction findings in the periphery of the mass.

Rare pulmonary tumors and carcinoma mimickers; experience from an interventional radiology unit with radiologic-pathologic correlation-A pictoral essay

BACKGROUND

Although imaging findings along with patients' clinical history may give clue for the etiology of a pulmonary lesion, the differentiation of benign pulmonary lesions from lung cancer could be challenging.

OBJECTIVE

The aim of this review article was to increase the awareness of the carcinoma mimicking lung lesions.

METHODS

This paper was designed to illustrate rare pulmonary tumors and carcinoma mimickers with emphasis on radiologic-pathologic correlation. Pitfalls encountered on CT images and also false positivity of PET-CT scans were also presented.

CONCLUSION

Several benign pulmonary lesions may grow in size on follow-up and some may show pathologic FDG (18F-fluorodeoxyglucose) uptake, which makes them indistinguishable from lung carcinoma by imaging. In addition, some slow-growing malignant lesions, such as carcinoid, may be false-negative on PET/CT scans.

18 F-FDG PET/CT imaging: A supplementary understanding of pulmonary sclerosing pneumocytoma

Background

We sought to investigate the clinical features and ¹⁸F‐FDG PET/CT characteristics of pulmonary sclerosing pneumocytoma (PSP).

Methods

We retrospectively reviewed and comparatively analyzed ¹⁸F‐FDG PET/CT imaging results of 22 patients with diagnosed PSP in our hospital from November 2009 to September 2015.

Results

The SUV_max in tumors was positively correlated with tumor size in typical PSPs (R = 0.806, R² = 0.650, P = 0.001); however, the SUV_max in tumors had no significant correlation with tumor size of atypical PSPs (R = 0.479, R² = 0.229, P = 0.162), and the degree of correlation between them attenuated when atypical PSPs were included (R = 0.518, R² = 0.268, P = 0.011). A majority (90%) of atypical PSPs were found in males. Symptomatic patients showed a higher SUV_max than the asymptomatic group (5.68 ± 3.63 vs. 2.76 ± 1.18, respectively, P = 0.002).

Conclusion

Tumor size and clinical features may be associated with increased FDG uptake in PSPs. Morphological differences may affect the correlation between tumor size and SUV_max in PSPs. The atypical form of PSP may be more common in men.