INTRODUCTION

The diagnosis of rib haemangioma is often forgotten in the differential diagnosis of a chest wall tumor. Half of primary chest wall tumors are malignant; hence, accurate diagnosis is imperative (1). Hemangiomas occurring in the ribs are extremely rare, with only a handful reported in the literature (2,3)

Histologically,haemangiomas appear as a proliferation of normal vascular elements with interspersed fatty overgrowth and can be categorized as one of five histologic subtypes : capillary, cavernous, venous, arteriovenous, or mixed (4,5).

As there is a wide range of radiological patterns, accurate preoperative diagnosis of non-classical skeletal haemangioma is difficult to make. Bone haemangiomas are usually asymptomatic, and either discovered incidentally or at autopsy.

In our case, the patient presented with upper back pain, shortness of breath and coughing.Patient underwent thoracotomy and histopathology showed mixed capillary and cavernous haemangioma involving only the cortical segment of left 2nd rib.

This case report adds  to the literature on this rare condition and discusses the issues in the diagnosis of chest wall tumors.

CASE REPORT

A 25-year-old female patient presented with upper back pain, shortness of breath and coughing. One month after the onset of her complaints, she was referred to our hospital. Patient had undergone thoracotomy for the similar complaint thirteen years back and was asymptomatic till the last one month period. The present fallout may be either a growth from incomplete excision of the lesion or a recurrence.

On general examination she was moderately built and nourished, vital parameters were stable and systemic  examination showed no gross irregularity except decreased breath sounds in the left upper chest  and left supra scapular region.

Bio-chemical Investigations were within normal limit .ECG showed normal Sinus Rhythm. 2D Echo revealed normal sized chambers. No RWMA with good biventricular function. No MR/AR/TR No PE / Clot.

Figure 1

X RAY CHEST

X ray chest showed a sharp well-defined homogenous opacity is noted in left upper zone, silhouetting the 1st left rib posteriorly. Air bronchogram was not noted within the lesion. No satellite lesions noted. Adjacent lung showed no focal parenchymal lesion. Aortic contour appeared normal. It appeared as posterior lesion as it is crossing above the clavicle Cervicothoracic sign.

Figure 2

Osteolytic lesion arising from the medial aspect of the left 2nd rib

Sagittal reformatted MDCT post-contrast image showed a well-defined globular expansive osteolytic involving posterior aspect of 2nd rib. The lesion is showed heterogenous intense post-contrast enhancement, with peripheral rim calcification & few scattered foci of calcification. The lesion seems to be extending posteriorly in the region of apicoposterior segment of left upper lobe. Mediastinum and visualized abdomen appeared normal.

Figure 3

A heterogenous expansive osteolytic soft tissue lesion is seen involving 2nd left rib posteriorly with scattered foci of calcification. The lesion is showing inhomogenous enhancement after contrast administration with few vascular sinuses. Lesion is located left and superior to arch of aorta. Visualised vessels, trachea, esophagus and other structures appear normal.

Figure 4a & b

Shows tumor blush.i.e. feeding vessels to the rib lesion(probably from posterior intercostsl artery), indicating vascularity of the lesion .(b) post-emolization angiographic film after check-up contrast injection which shows significant reduction in tumor blush

The patient underwent thoracotomy and a firm to hard mass, measuring 7 x 9 x7 cm was identified as destroying the middle and posterior parts of the Left 2nd rib and protruding into the thoracic cavity. Adhesions were present between tumour and Posterior segment of left upper lobe of lung.

Figure 5

Posterlateral thoracotomy

Figure 6

Excised Specimen showing the exophytic 2nd rib lesion

Figure 7

Gross pathological examination shows lesion has infiltrated part of rib

Figure 8

Mixed capillary and cavernous pattern of Intraosseous haemangioma

Figure 9

Microscopy shows a conglomerate of thin-walled blood vessels with adjacent bony trabeculae. Vascular channels comprise dilated vessels.

Figure 10

Patient showing the operated wound on 5th postoperative day

No post operative complications occurred and patient was discharged on the 7th post operative day with supportive medicines and further follow up advice.

DISCUSSION

Osseous hemangiomas are usually identified in middle-aged patients more often women. Most of this lesions are discovered as an incidental finding for unrelated reasons, but in the presence of a pathologic fracture there may be soft tissue swelling or pain .  The fact that our case was symptomatic may be attributable to its size (7 x 9 x 7 cm). We believe that the pleural irritation by the tumour was the cause of the upper back pain and its compression on the bronchi of the coughing and dyspnea.

Bone haemangioma are usually solitary but up to one-third of cases can have multiple lesions. Bone haemangioma usually occur in the medullary cavity and, less commonly, in the cortex, periosteum and subperiosteal regions.(6) In our case, the lesion was confined to the cortex with no medullary extension signifying the rarity of the lesion.

Establishing the diagnosis before surgery is difficult and, given the non-specific nature of the radiographic features, it is easy to confuse these tumours with other malignant bone lesions which may require extensive resection (7).

Radiographically a radiolucent, slightly expansile and well defined intraosseous lesion with a radiating trabecular pattern is highly suggestive of hemangioma for extraspinal sites . CT or MRI are useful for assessing changes in bone trabeculae.

MRI features of hemangiomas depend on the proportion of fat and vascularity of the lesions. Fat content reveals high signal intensity on T1-weighted MR images, whereas vascular parts show high signal intensity on T2-weighted images.

Because hemangiomas rarely occur in the ribs, they are often misdiagnosed. The differential diagnosis of a rib lesion includes primary tumors and metastatic lesions. Examples of primary malignant bone tumors include myeloma, chondrosarcoma, osteosarcoma and Ewing sarcoma.

 Benign primary rib lesions include osteochondroma, enchondroma, fibrous dysplasia, eosinophilic granuloma and aneurysmal bone cysts. Some rib lesions, such as fibrous dysplasia, aneurysmal bone cysts and osteochondroma, may have characteristic imaging findings that allow a specific diagnosis (8,9).

Preoperative diagnosis of a chest wall tumor by imaging alone is often not possible, and definitive diagnosis by biopsy or resection may be required With regard to deciding on a biopsy versus a resection of a solitary rib lesion, a biopsy (fine needle, core or open) of a hemangioma can result in significant bleeding (10). Moreover, many bone tumors are inhomogeneous on histological examination; hence, studying small samples (as opposed to a wholly excised specimen) can be misleading (11).

 A complete resection of the rib lesion, if feasible, may be the best option once other investigations confirm that the lesion is solitary. Some other management options for symptomatic hemangiomas include radiotherapy, transarterial embolization and alcohol injection.

In conclusion, we add a very rare case of mixed intraosseous  hemangioma  to the existing literature. The exceptional rarity of these lesions should make us reflect on their etiology and pathogenesis, trying to understand why hemangiomas are more frequent in some areas and so rare in others.