Pulmonary Hamartoma: a Single-Center Analysis of 142 Cases

Background. Gamartoma occupies a special place among solitary lung masses not requiring active surgical tactics: structural heterogeneity due to inclusions of fat density and calcinates presents an opportunity to identify pathognomonic computed tomographic (CT) signs. However, their absence in conjunction with CT picture inherent in malignant neoplasms can cause biopsies and surgical interventions that are not necessary according to the results of histologic examination.
Objective: to perform a cohort retrospective analysis of pulmonary hamartoma CT semiotics.
Маterial and methods. We analyzed 142 cases of lung hamartomas detected at the Saint Petersburg Research Institute of Phthisiopulmonology from 2013 to 2023, confirmed histologically or with a follow-up period of more than 600 days, without endobronchial location and other foci/formations in the lungs, without contrast enhancement evaluation.
Results. The results of data statistical analysis of patients with pulmonary hamartoma with distribution by gender and age were described. The occurrence rate was established for such hamartoma CT features as mass type, contour features, changes in the surrounding lung tissue, the largest diameter, density, calcination type with examples on CT images. Localizations of hamartomas in relation to the lung, its lobes and segments were considered. Four hamartoma clusters depending on fat and calcination combination in the structure were identified and illustrated. The size distribution of hamartomas from each cluster within the given ranges was also presented.
Conclusion. Lung hamartomas are solid-type masses without preferential localization in lung segments, with the possibility of detection at any age. In a significant proportion of cases (43.7%) hamartomas did not have any structural features, which allow, according to CT data, to convincingly classify them as benign masses and avoid surgical resection. Only in 12% of cases hamartomas had structural changes considered highly pathognomonic for their classification as benign masses.

1. WHO Classification of Tumours Editorial Board. Thoracic Tumours: WHO Classification of Tumours. 5th ed. World Health Organization; 2021: 154–5.

2. Takumi K, Nagano H, Harasawa T, et al. Pulmonary hamartoma: feasibility of dual-energy CT detection of intranodular fat. Radiol Case Rep. 2021; 16(5): 1032–6. https://doi.org/10.1016/j.radcr.2021.01.062.

3. Ulas AB, Aydin Y, Eroglu A. Pulmonary hamartomas: a singlecenter analysis of 59 cases. Eurasian J Med. 2022; 54(3): 270–3. https://doi.org/10.5152/eurasianjmed.2022.21150.

4. Grigoraş A, Amălinei C, Lovin CS, et al. The clinicopathological challenges of symptomatic and incidental pulmonary hamartomas diagnosis. Rom J Morphol Embryol. 2022; 63(4): 607–13. https://doi.org/10.47162/RJME.63.4.02.

5. Esme H, Duran FM, Unlu Y. Surgical treatment and outcome of pulmonary hamartoma: a retrospective study of 10-year experience. Indian J Thorac Cardiovasc Surg. 2019; 35(1): 31–5. https://doi.org/10.1007/s12055-018-0728-x.

6. Hochhegger B, Nin CS, Alves GR, et al. Multidetector computed tomography findings in pulmonary hamartomas: a new fat detection threshold. J Thorac Imaging. 2016; 31(1): 11–4. https://doi.org/10.1097/RTI.0000000000000180.

7. Cangir AK, Orhan K, Kahya Y, et al. A CT-based radiomic signature for the differentiation of pulmonary hamartomas from carcinoid tumors. Diagnostics (Basel). 2022; 12(2): 416. https://doi.org/10.3390/diagnostics12020416.

8. Gaerte SC, Meyer CA, Winer-Muram HT, et al. Fat-containing lesions of the chest. Radiographics. 2002; 22 (Spec No): S61–78. https://doi.org/10.1148/radiographics.22.suppl_1.g02oc08s61.

9. Yang X, Li C, Hou J, et al. Differentiating peripherally located pulmonary noncalcified hamartoma from carcinoid using CT radiomics approaches. J Comput Assist Tomogr. 2023; 47(3): 402–11. https://doi.org/10.1097/RCT.0000000000001414.

10. Elsayed H, Abdel Hady SM, Elbastawisy SE. Is resection necessary in biopsy-proven asymptomatic pulmonary hamartomas? Interact Cardiovasc Thorac Surg. 2015; 21(6): 773–6. https://doi.org/10.1093/icvts/ivv266.

11. Gjevre JA, Myers JL, Prakash UB. Pulmonary hamartomas. Mayo Clin Proc. 1996; 71(1): 14–20. https://doi.org/10.4065/71.1.14.

12. Habert P, Decoux A, Chermati L, et al. Best imaging signs identified by radiomics could outperform the model: application to differentiating lung carcinoid tumors from atypical hamartomas. Insights Imaging. 2023; 14(1): 148. https://doi.org/10.1186/s13244-023-01484-9.