Atypical lipomatous tumour (lipoma-like well-differentiated liposarcoma) arising in a pulmonary hamartoma and clinically presenting with pneumothorax

Pulmonary leiomyosarcoma arising in pulmonary hamartoma: an exceptional occurrence in a rare tumor

A solitary peripheral lung nodule was found in the left lung of a 52-year-old man. It was located in the lower lobe and measured 18.5 cm of major axis on chest computed tomography. A tru-cut core biopsy was obtained and a proliferation of bland, monomorphic, spindle cells in interlacing fascicles was observed. Accordingly, a surgical resection of the neoplasm was subsequently carried out. Macroscopically, the tumor appeared as a well-circumscribed nodule with a firm and whitish cut surface. Histologically, the neoplasm was predominantly composed of bland and monomorphic spindle cells, with a predominantly fascicular growth pattern, in which many tubular and cleft-like spaces of entrapped normal respiratory epithelium were involved. Myxoid change, stromal hyalinization and scattered bizarre mononucleated and multinucleated cells were also observed. Based on clinico-morphological, immunophenotypical and molecular features, we made a diagnosis of malignant transformation of pulmonary adenoleiomyomatous hamartoma into pulmonary leiomyosarcoma. As far as we know, this is the first described case of this exceptionally rare occurrence in an already rare neoplasm.

Primary intrathoracic liposarcomas: A clinicopathologic and molecular study of 43 cases in one of the largest medical centers of China

Introduction

Primary intrathoracic liposarcoma is extremely rare, and most published series lack genetic analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Materials and methods

Forty-three primary intrathoracic liposarcomas were identified and most cases were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), whole-exome sequencing (WES), and Sanger sequencing.

Results

This series included 27 males and 16 females (ratios, 1.68:1) aged 24-73 years (median, 53 years). Tumors mainly occurred in the mediastinum (n=23, 53.5%), followed by pleural cavity (n=16, 37.2%) and lung (n=4, 9.3%). The study included 21 well-differentiated liposarcomas (WDLs), 19 dedifferentiated liposarcomas (DDLs), 2 myxoid pleomorphic liposarcomas (MPLs) and 1 pleomorphic liposarcoma (PL), without identification of myxoid liposarcoma. FISH analysis identified MDM2 amplification in 17 of 18 WDLs (94.4%) and all DDLs (16/16, 100.0%). The MDM2-nonamplified WDL was CDK4-nonamplified but FRS2-amplified. WES and Sanger sequencing found somatic TP53 mutation in the 2 MPLs. Follow-up information was available for 33 of 38 cases (86.8%). Thirteen patients (39.4%) showed no evidence of disease, 10 patients (30.3%) were alive with disease, and 8 patients (24.2%) died of disease. Fourteen cases developed recurrence and 1 with metastasis.

Conclusions

WDL/DDL was the overwhelming subtype in this location, followed by MPL and PL. Analysis of the FRS2 gene, in combination with MDM2 and other genes of 12q13-15, may more precisely characterize WDL/DDLs. MPL is the most fatal subtype of this site. Further studies are needed to explore the role of TP53 in the pathogenesis of MPL.

Mucinous Adenomyomatous Pulmonary Hamartoma: Clinicopathologic, Immunohistochemical, and Molecular Features of 6 Cases

Pulmonary hamartoma (PH) may show various combinations of mesenchymal tissues with entrapment of respiratory epithelium. An uncommon variant of PH prevalently consisting of smooth muscle with mucinous proliferation has been reported in literature under several definitions as sporadic reports. We collected a series of 6 leiomyomatous PH associated with mucinous growth from consultation files (3 cases) and multicentric revision of archival files among 128 consecutive surgically resected PH. The lesions have a prevalence for male gender (5:1) and lower lobes (5:1), with a mean age at diagnosis of 61 years. All cases were incidentally disclosed in asymptomatic patients and had an indolent behavior. At histology, 2 cases consisted uniquely of smooth muscle and 4 also showed mature adipose tissue. The mucinous proliferation consisted of a monotonous growth of columnar cells lacking p63-positive basal cells and expressing pan-CKs, MUC5A, and CK7, but negative with TTF-1, napsin, MUC1, MUC2, MUC6, CK20, and CDX2. Smooth muscle was negative with hormonal receptors. Molecular analysis using a multiplex gene panel did not reveal gene mutations, while ALK, BRAF, and ROS1 were negative. In conclusion, we describe a small series of uncommon PH with prevalent leiomyomatous mesenchymal component associated with a mucinous growth (mucinous adenomyomatous hamartoma). Despite the lack of basal cells coating mucinous proliferation and irregular architecture, the favorable outcome and lack of molecular alterations most likely lay for a benign/low-grade tumor. Pathologists should be aware of this unusual occurrence to prevent a diagnosis of overt malignancy, particularly in frozen section, small biopsy, and cytology.

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

The radiological features of pulmonary sclerosing hemangioma (PSH) and pulmonary hamartoma are poorly specified. Thus, the present study aimed to compare and analyze the characteristics of fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in PSH versus pulmonary hamartoma. ¹⁸F-FDG PET/CT characteristic findings of 12 patients with PSH and 14 patients with pulmonary hamartoma were retrospectively reviewed. A total of 12 lesions were detected from the 12 patients with PSH, of which 3 masses exhibited calcification. The mean diameter and standardized maximum uptake value (SUVmax) were 1.9±0.7 cm and 2.6±1.0, respectively, and there was no significant correlation between the lesion size and SUVmax (P>0.05). For the 14 patients with pulmonary hamartoma, 14 lesions were found, of which 4 exhibited calcification. The mean diameter and SUVmax were 1.7±0.8 cm and 1.5±0.6, respectively, and there was a significant correlation between the size and SUVmax (r=0.625, r²=0.391, P<0.05). Although there was no significant difference between the size of PSH and pulmonary hamartoma (P>0.05), the SUVmax of PSH was significantly higher than that of pulmonary hamartoma (P<0.05). Moreover, the SUVmax of 1.95 was applied as a cutoff for the diagnosis of PSH, and the resulting sensitivity and specificity for PET/CT to differentiate PSH from pulmonary hamartoma were 83.3 and 78.6%, respectively. Although the morphological features were not specific, PSH showed significantly higher FDG accumulation than pulmonary hamartoma on PET/CT imaging, which may aid the differential diagnosis. Further studies with larger populations are warranted to confirm these study results.

Endobronchial hamartoma as a cause of pneumonia

Patient: Male, 66

Final Diagnosis: Endobronchial hamartoma

Symptoms: Fever

Medication: —

Clinical Procedure: Flexible bronchoscopy • surgical resection

Specialty: Pulmonology

[Pulmonary hamartoma with lipomatous form]

We report of the case of a 41-year-old patient, who had previously undergone thoracic surgery at the age of 16 for a single giant emphysematous bulla. The CT scan showed an abnormal middle mediastinal lesion containing an aerated cystic areas and areas of fat density. The patient underwent surgery and a well-defined mass was found between the mediastinum and the pulmonary hilum, which was able to be completely resected. Microscopic examination disclosed a composite tumour containing a bronchogenic cyst, a benign lipoma and two hamartochondromas. As no similar case had been reported previously, it was difficult to assert the nature of the lesion, which has been labelled as a "hamartoma". The main diagnoses which should be considered when an intra pulmonary fat density mass is disclosed, are discussed.

Pulmonary hamartoma diagnosed by convex probe endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)

A 71-year-old man with a right hilar mass shadow was referred to our department. Chest computed tomography showed a small fatty area inside. Convex probe endobronchial ultrasound (CP-EBUS) images revealed a heterogeneous low-echoic mass, resembling a stone wall and showing a smooth sliding movement along the tracheal wall during respiration. Transbronchial needle aspiration (EBUS-TBNA) was performed and cartilage cells were identified, compatible with the presence of a hamartoma. The patient requested follow-up without surgical intervention. CP-EBUS images are easier to interpret than other methods for monitoring respiratory dynamics. We conclude that CP-EBUS is a useful addition to techniques both for non-invasive imaging as well as guiding pathological examination.

Diagnostic efficacy and characteristic feature of MRI in pulmonary hamartoma: comparison with CT, specimen MRI, and pathology

OBJECTIVES

To determine the diagnostic efficacy of magnetic resonance imaging (MRI) in pulmonary hamartoma and observe the significant MRI features, other than fat or characteristic calcification revealed by computed tomography (CT).

METHODS

Six hamartomas were included and surgically resected, and we prospectively studied MRI in cases showing suggestive findings of hamartoma or indeterminate nodule on CT. We analyzed the tumor on CT and MRI (available enhancement study in 4) focusing on cleftlike structure in comparison with specimen MRI (n = 3) and histopathologic findings: presence, shape, and distribution of the cleftlike structure and signal intensity and enhancement of the cleftlike structure and main portion.

RESULTS

Computed tomography revealed suggestive findings of pulmonary hamartoma (fat or popcorn calcification) in only 3. All MRI revealed cleftlike structures particularly evident on T2-weighted images with same detectability as its specimen MRI: peripheral linear or curvilinear inclusions with sometimes intratumoral cleftlike space (n = 3), variable signal intensity, and frequent enhancement (3 in 4) pathologically correlated with the variable mesenchymal tissue components and amount arrayed along respiratory epithelial cells lining the cleft and richer vascularity than main portion of pulmonary hamartoma.

CONCLUSIONS

Magnetic resonance imaging study is a useful diagnostic tool, when a discrete pulmonary nodule demonstrates neither fat nor calcification on CT, for detecting the quite typical cleftlike structure in a pulmonary hamartoma and could provide diagnostic confidence.

Surgical treatment and outcome of pulmonary hamartoma: a retrospective study of 20-year experience

BACKGROUND

Controversy still exists in the indication and timing of surgical treatment of pulmonary hamartoma (PH). The objective of this study is to summarize the experience and the outcome of the surgical treatment for pulmonary hamartomas, and to assess the effectiveness and necessity of surgical therapy administered in patients with pulmonary hamartoma as well as clinical and pathological features and long-term follow-up results.

METHODS

This retrospective report has reviewed a 20-years clinical history of surgical treatment for 39 patients with PH from 1985 to 2006. These thirty-nine patients underwent 40 operations as follows: wedge resection (23), enucleation (10), segmentectomy (3), lobectomy (3), and pneumonectomy (1).

RESULTS

The PH occurred most frequently (78.1%) in the patients aged 40 to 60 years and the sex ratio (male/female) was 2.25/1 in our series. No postoperative death was encountered. One patient with pleural effusion was cured after thoracentesis. All of these 39 patients were proved with pathologic diagnosis of PH and the popcorn calcification was found in 6 cases before operation. In 38 cases having the mean follow-up of 7.3 years, a patient was operated thrice for regional recurrence.

CONCLUSION

Fast frozen section in operation is critical for acquire accurate pathological diagnosis. Due to potential trend of recurrence or malignancy, patients with hamartoma should be submitted to a complete evaluation and a regular follow-up.

Dedifferentiated chondrosarcoma of the lung: case report and review of the literature

Primary malignant chondromatoid tumors of the lungs are rare. We report on a case of a 49-year-old woman who presented with a round focus in the upper lobe of the left lung. The performed biopsy showed features of a leiomyosarcoma. After chemotherapy and consecutive tumor resection, the histologic investigation of the entire tumor mass revealed a dedifferentiated chondrosarcoma. Careful clinical and radiologic examinations showed no evidence of further pulmonary and extra-pulmonary tumor lesions. The final diagnosis of a primary dedifferentiated chondrosarcoma of the lung was based on the morphologic criteria and review of the literature. The differential diagnosis of malignant hamartoma was discussed. Follow-up investigation after 2.5 years showed no evidence of another primary tumor site.

Formation of the 12q14-q15 Amplicon Precedes the Development of a Well-differentiated Liposarcoma Arising From a nonchondroid Pulmonary Hamartoma

Pulmonary hamartoma is a benign neoplasm that rarely recurs or undergoes malignant transformation. Herein, we report a 48-year-old woman with a history of an incomplete excised nonchondroid pulmonary hamartoma presenting as an indolent tumor recurrence. Excision of the tumor revealed a well-differentiated liposarcoma arising from the hamartomatous component. Fluorescence in situ hybridation analysis for HMGA2 and MDM2 was performed on both hamartomatous and liposarcomatous component. MDM2 and HMGA2 amplification were found in a subset of stromal cells in the hamartomatous component and in most cells of the well-differentiated liposarcoma. No rearrangement HMGA2 was found in the pulmonary hamartoma component. These findings suggest that the formation of the 12q14-q15 chromosome amplicon, the characteristic cytogenetic finding of well-differentiated liposarcomas and the structural genomic component of the supernumerary ring and giant rod chromosomes, occurred before the morphologic changes characteristic of these malignant adipose tissue tumors and likely represents a very early molecular event in their development.

Diffuse pulmonary hamartoma: a case report

Pulmonary hamartoma usually occurs as a benign, well-circumscribed single nodule in the lung parenchyma. We report on a unique case of hamartoma that extended along the bronchial tree, formed endobronchial polypoid lesions, and expanded into the lung parenchyma. The patient, a 48-year-old man, was admitted with dyspnea and chest pain. A transbronchial biopsy was performed on a tumorous lesion that was diagnosed histologically as a hamartoma. As this lesion was found to be growing diffusely along the bronchial tree, a left pneumonectomy was performed. Gross examination showed that yellowish soft tissue had surrounded the bronchial tree and extended into the lung parenchyma. Histologically, the lesion contained mainly mature adipose tissue, cartilage, and muscle tissue with a minor component of short spindle cells in a myxomatous matrix. The patient was diagnosed as having diffuse pulmonary hamartoma.