Rib desmoplastic fibroblastoma: Video-assisted resection.

A 46-year-old man was referred to our department due to chronic chest pain. A computed tomography showed an exophytic image arising from 5th rib that was projected on the middle lobule. The patient underwent an exploratory videothoracoscopic because we couldn't discard lung compromise. A corneal-like lesion emerging from the inner side of the 5th rib was revealed. Complete video-assited resection was done. Histopathology examination revealed a desmoplastic fibroblastoma. To our knowledge this is the first case of desmoplastic fibroblastoma arising from a rib and the second case published in all literature of chest wall involvement.

INTRODUCTION

Evans first described desmoplastic fibroelastomas in 1995. These unusual well-circumscribed benign soft tissue tumours usually develop in the subcutaneous cellular tissue or skeletal muscle of extremities.[1] They have also been described in head and neck, tongue, lacrimal gland, palate and parotid gland.

To the best of our knowledge, this is the first case of desmoplastic fibroblastoma arising from a rib and the second case published in all literature of chest wall involvement.

CASE REPORT

A 46-year-old male, former smoker (30 pack/year) with no other relevant medical history was referred to our department due to chronic chest pain. A chest X-ray was performed where a right pulmonary opacity was found. Computed tomography showed an exophytic image arising from the 5th rib that was projected on the middle lobule [Figure 1].

Figure 1

Computed tomography - exophytic image arising from the 5th rib projecting into the middle lobe

The patient was in good general status and its clinical interview does not reveal any abnormality. Respiratory functional tests were normal with a forced expiratory volume in 1 s of 3.6 L (89%) and forced vital capacity of 4.5 L (90%).

With the suspicion of a chondrosarcoma, surgical resection was indicated. An initial videothoracoscopic approach was performed for not being able to discard a parenchymal involvement. Videothoracoscopic examination revealed a corneal-like lesion emerging from the inner side of the 5th rib [Figure 2a]. The pulmonary parenchyma (middle lobe) presented a footprint of the lesion by contiguity but was not compromised [Figure 2b]. A 1 cm incision was made at the height of the involved rib and a complete video-assisted resection of the affected rib segment was done with margins. The reconstruction of the thoracic wall was done with a polypropylene mesh [Figure 2c–e]. The patient underwent uneventful recovery. Pleural drainage was removed on the 2nd day and was discharged on the 3rd post-operative day. Histopathology examination revealed a desmoplastic fibroblastoma arising from the rib. The osseous tissue and surrounding soft tissues were normal [Figure 3].

Figure 2

(a) Thoracoscopic view of the corneal-like lesion emerging from the inner side of the 5th rib. (b) Rib tumour footprint (middle lobe). (c-e) Chest wall reconstruction with a polypropylene mesh

Figure 3

(a) Specimen (rib segment). (b) Histopathologic examination with haematoxylin and eosin staining. Tumour lesion consisting of uniform fibroblasts, some starred, immersed in a densely collagenised matrix

DISCUSSION

Desmoplastic fibroblastoma is a rare benign soft tissue tumour arising in the subcutaneous tissue or skeletal muscle in adults. It has a wide anatomic distribution but mainly affects the extremities. Location in the chest wall is rare, and it has been reported only once in the literature.[2] The lesions are often mobile and subcutaneous but occasionally can be deep-seated intramuscular masses.[3] The patient presented a painless tumour growing into the pleural cavity.

Desmoplastic fibroblastoma presents as a slowly growing, usually painless tumour with a favourable outcome. Various studies have reported no recurrences even after marginal resections.[3] Invasion and destruction of bone are uncommon features.[4]

Microscopically, the tumour is hypocellular and characterised by fibroblastic spindle cells distributed in an abundant collagenous and fibromyxoid stroma with low to moderate vascularity.[3] The differential diagnosis for desmoplastic fibroblastoma includes desmoid tumours that bears some resemblance but is morphologically different. Desmoid tumours have more cellularity and vascularity, and their cells have the tendency to grow in fascicles.[34] Moreover, prognosis of both tumours is different. Desmoplastic fibroblastoma is less aggressive with low recurrence rate while desmoid tumours have higher recurrence rates in spite of radical resections or other treatments, such as radiation.[4]

Radiographic characteristics may also help in the differential diagnosis of these tumours. Imaging generally reveals a well-circumscribed mass. It is heterogeneous on magnetic resonance imaging-scans with both low-(areas of dense collagen) and high-(fibromyxoid matrix) intensity areas on T2-weighted images.[5]

To the best of our knowledge, this is the second case of desmoplastic fibroblastoma occurring in the chest wall and invading the pleural cavity and the first case that arise from a rib. After 1-year of follow-up, no recurrence has been detected.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.