Hamartochondroma Pleural Lesion Mimicking Liposarcoma: A Case Report

Round 1

Reviewer 1 Report

The author present a case report about an unsusual hartochondrom of the lung. The Report is well structured and considers all relevant positions for thourough reworking.

The report is of interest to the thoracic community because of its rare phenomen and the systematic diagnostic and therapy

Author Response

Thank you for your kind comment. We also think that this is an interesting case because of the unusual presentation of this tumor and we wanted to highlight how difficult it is sometimes to have a preoperative diagnosis of certainty of a thoracic tumor.

Reviewer 2 Report

Comments to Authors:

The authors reported a case report “Hamartochondroma pleural lesion mimicking liposarcoma: a case report”. They presented reported a rare case of hamartochondroma. A complete preoperative workup revealed a large tissular and fatty mass in the right costo-diaphragmatic angle suggestive of liposarcoma. Surgical resection resulted in the surprising diagnosis of hamartochondroma.

Thank you very much for the interesting case presentation.

I have the following concerns.

Comments

#1

Hamartochondroma was a rare pulmonary tumor. Using PubMed, it had been reported since about the 1950s. In recent years, in addition to CT and MRI, PET scans have improved qualitative diagnostic rates.

In this report, the author strongly suspected liposarcoma, as indicated in the title. However, based on the combination of MRI and PET, it is questionable whether that preoperative diagnosis was reasonable. Although MRI might have suspected (dedifferentiated) liposarcoma, PET did not show any findings to support this. The same is true for other malignant tumors, including thymoma. In light of the pathological results, the preoperative imaging findings make sense.

#2

Are there other reports of large hamartochondroma like this case

#3

What is the relationship between symptoms and the tumor?

#4

Please present any findings on MRI that were suspicious of invasion into adjacent organs.

#5

Please present any findings on the DWI of MRI.

#6

What were the echographic findings at the time of biopsy?

#7

What is the relationship between the patient's symptoms and the tumor? Intraoperatively, the authors admitted adhesions around the tumor. Were there any preoperative findings suggestive of inflammation?  Were the preoperative C-reactive protein levels and other parameters normal?

Author Response

#1 Hamartochondroma was a rare pulmonary tumor. Using PubMed, it had been reported since about the 1950s. In recent years, in addition to CT and MRI, PET scans have improved qualitative diagnostic rates.

In this report, the author strongly suspected liposarcoma, as indicated in the title. However, based on the combination of MRI and PET, it is questionable whether that preoperative diagnosis was reasonable. Although MRI might have suspected (dedifferentiated) liposarcoma, PET did not show any findings to support this. The same is true for other malignant tumors, including thymoma. In light of the pathological results, the preoperative imaging findings make sense.

Our difficulty was that on the one hand the appearance on MRI was very suggestive for our radiologists of a liposarcoma and on the other hand the absence of fixation on PET scan was rather in favor of a less aggressive lesion. In addition, some well differenciated liposarcoma can present with a low FDG uptake (Li CP, et al. Contrast Media Mol Imaging. 2021). So, In this young patient with an operable tumor, we opted for a surgical resection allowing a precise diagnosis and its treatment at the same time. However, we agree that in hindsight, the preoperative imaging findings make sense.

A clarification on this point has been made in the text (line 58-63).

#2 Are there other reports of large hamartochondroma like this case?

Majority of these tumors are very slow growing and usually diagnosed at a small size (between 4 and 90 mm) but few giant cases of pulmonary hamartoma in adults have been reported (Geramizadeh B, et al. Rare Tumors. 2019 Jan 10;11:2036361318823926). No giant mediastinal or pleural hamartoma has been reported.

Changes have been made line96-99.

#3 What is the relationship between symptoms and the tumor?

We initially thought that the right subcostal pain was related to the presence of this large and probably heavy basithoracic tumor, but the pain recurred after the operation and was finally attributed to a pancreatitis.

This information has been added in the text (line 75-77).

#4 Please present any findings on MRI that were suspicious of invasion into adjacent organs.

There was no evidence for chest wall invasion on MRI.

This element has been specified in the text (line 39-41).

#5 Please present any findings on the DWI of MRI.

Unfortunately, DWI sequences have not been realized.

#6 What were the echographic findings at the time of biopsy?

The thoracic ultrasound confirmed a heterogeneous tissue mass, not invading the chest wall.

This information has been added in the text (line 55-56).

#7 What is the relationship between the patient's symptoms and the tumor? Intraoperatively, the authors admitted adhesions around the tumor. Were there any preoperative findings suggestive of inflammation?  Were the preoperative C-reactive protein levels and other parameters normal?

The patient has medical history of gallstones. The symptoms suggested atypical biliary colic. This was also supported by the fact that the pain recurred few weeks after the operation. An opinion from a gastroenterologist led to the diagnosis of pancreatitis secondary to a pancreas divisum. There was no preoperative evidence of inflammation. Leukocytes and CRP were within normal limits.

This information has been added in the text (line 75-77).

Reviewer 3 Report

Dear Authors,

This submission is a case report of a common pathologic diagnosis with a very unique presentation.   Overall, the case presentation is very well done and the review is concise but informative.   A few points to the authors:

1) There are several case reports of pleural based/chest wall hamartomas in the pediatric population (neonatal).  Are there any similarities or differences to the current case presentation?

2) PET imaging showed a generally non-avid tumor.   Liposarcoma is typically a very PET avid tumor, especially in the more aggressive subtypes.   In addition, most other malignant pleural based tumors are also PET-avid (malignant fibrous tumor, thymoma, etc).   Although I agree that the CT findings may indicate an 'aggressive lesion' (line 62), based on PET imaging, I would consider that the mass to be much less threatening.   Perhaps the authors can comment on the utility of PET imaging in the clinical decision making.  

3) Asymptomatic pulmonary hamartomas that are diagnosed by needle biopsy can be clinically followed and do not require surgical resection.  I agree that surgical resection should be considered in the symptomatic patient or if the diagnosis is question.  However, given the benign diagnosis, I don't think that regular follow up is mandatory or the usual practice after complete resection, as the authors conclude. (line 109).

4) In the References section, reference 2 & 3 are duplicates.   Was another paper was intended to be cited?

Author Response

1) There are several case reports of pleural based/chest wall hamartomas in the pediatric population (neonatal).  Are there any similarities or differences to the current case presentation?

The similarities are that it is a well-defined mass comprising cartilage islands. The few differences that we found in the literature is that in children it is a chest wall hamartoma, mesenchymal, diagnosed at larger sizes and may destroy adjacent ribs. On the contrary, in adults, we found, predominantly, pulmonary hamartoma with more mature tissue, diagnosed mostly between 4 and 90mm and not invading the surrounding structures. They are therefore similar but different entities and that is why we have not mentioned infant cases in the manuscript. Similarly, we report the case of a hamartoma without adhesion to the chest wall, without destruction of adjacent rib and formed of mature tissue. Our case, like that of adults in general, is different from those encountered in pediatrics.

2) PET imaging showed a generally non-avid tumor.   Liposarcoma is typically a very PET avid tumor, especially in the more aggressive subtypes.   In addition, most other malignant pleural based tumors are also PET-avid (malignant fibrous tumor, thymoma, etc).   Although I agree that the CT findings may indicate an 'aggressive lesion' (line 62), based on PET imaging, I would consider that the mass to be much less threatening.   Perhaps the authors can comment on the utility of PET imaging in the clinical decision making. 

Indeed, we were divided between the appearance on MRI that was very suggestive for our radiologists of a liposarcoma and the absence of FDG uptake on TEP scan that was rather in favor of a less aggressive lesion. As some subtypes of liposarcoma can present with a low FDG uptake (Li CP, et al. Contrast Media Mol Imaging. 2021), a surgical resection was decided to allow a precise diagnosis and its treatment at the same time.

A clarification on this point has been made in the text (line 58-63).

3) Asymptomatic pulmonary hamartomas that are diagnosed by needle biopsy can be clinically followed and do not require surgical resection.  I agree that surgical resection should be considered in the symptomatic patient or if the diagnosis is question.  However, given the benign diagnosis, I don't think that regular follow up is mandatory or the usual practice after complete resection, as the authors conclude. (line 109).

Indeed, there is no guidelines in terms of follow up for resected hamartomas and we do not do this in usual practice. Our concern was that this large mass was particularly at risk of recurrence and that a relationship between hamartoma and malignancy has been shown in some articles (Ribet M, et al. J Thorac Cardiovasc Surg. 1994 Feb;107(2):611-4 / Karasik A, et al. J Thorac Cardiovasc Surg. 1980 Aug;80(2):217-20). It therefore seemed safer to continue surveillance in this patient.

We changed the end of the discussion accordingly (line 120-124).

4) In the References section, reference 2 & 3 are duplicates.   Was another paper was intended to be cited?

This is an error of inattention, we have corrected it.

Round 2

Reviewer 2 Report

This paper is appropriately well revised.

Comment

As per the author's opinion, soft tissue sarcomas, including liposarcoma, are an important differential diagnosis. Based on previous reports, the author should describe to the reader the characteristic imaging findings of this disease.

Have there been any cases in which a preoperative diagnosis was possible based on imaging findings?

Please discuss the similarities and atypicalities of the preoperative imaging findings in comparison to previous case reports.

Author Response

The imaging appearance of liposarcoma varies based on their histological subtype. Well-differentiated liposarcomas may appear as large size mass, predominantly fatty with the presence of internal septations, mass-like or nodular areas of nonadipose tissue, and a decreased proportion of fat to nonadipose tissue. More aggressive liposarcomas may lack any identifiable fat on MR imaging. (Lee TJ, Collins J. MR imaging evaluation of disorders of the chest wall. Magn Reson Imaging Clin N Am. 2008 May;16(2):355-79, x).

Hamartomas, on the other hand, are unencapsulated, lobulated tumors with connective tissue septa. Fat is identified in up to 50% of hamartomas at CT and may be localized or generalized within the nodule. (Gaerte SC, et al. Fat-containing lesions of the chest. Radiographics. 2002 Oct;22 Spec No:S61-78).

On large suspicious mass, diagnosis is not based only on imaging findings. Fine needle or thoracoscopic biopsy is realized in order to have a diagnosis and to decide whether the patient should undergo neoadjuvant chemotherapy (Berry MF, et al. Giant thoracic liposarcoma treated with induction chemotherapy followed by surgical resection. J Thorac Oncol. 2009 Jun;4(6):768-9).

Precisions have been added in the text (line 96;99-104 and 106-110).

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

This paper is appropriately well revised.