Keywords hemangioma - scapula - Kasabach–Merritt syndrome - consumptive coagulopathy - angio-embolization
Introduction
Hemangiomas are benign vascular tumors that can develop anywhere in the body. Most are superficial and commonly found in the head and neck region. About one-third of these hemangiomas can be internal, typically located in the liver. Bony hemangiomas are not uncommon, making up 10% of all bone tumors.[1 ] They are often discovered incidentally in the spine or craniofacial bones.[2 ] Scapular hemangiomas are extremely rare. Hemangiomas of long or flat bones often exhibit a “foam” or “honeycomb” appearance.[3 ] These bone hemangiomas can grow expansively, causing cortical disruption, which may lead to misdiagnosis as aggressive tumors or infectious lesions.
Kasabach–Merritt syndrome is a rare condition involving a large vascular tumor (hemangioma) that results in severe low platelet counts (thrombocytopenia) and bleeding disorders, which can be life-threatening. Treatment of the underlying vascular tumor generally resolves Kasabach–Merritt syndrome. Various treatment options include angio-embolization, corticosteroids, α-interferon, chemotherapy with vincristine, radiotherapy, and surgery.
This is rare case report of scapular hemangioma with Kasabach–Merritt syndrome that was managed by multimodal therapy.
Case Report
An 8-year-old girl presented to the orthopaedic oncology clinic at the HBCH (Homi Bhabha Cancer Hospital) & MPMMCC (Mahamana Pandit Madanmohan Malaviya Cancer Centre), Varanasi, India, a unit of Tata Memorial Centre, a tertiary cancer center. She had been experiencing slowly progressive swelling and bluish-black discoloration of the skin over her left upper back for 3 years ([Fig. 1A ]). Additional symptoms included restricted mobility of the left shoulder, localized pain, and tenderness.
Fig. 1 (A ) Left scapular mass at presentation. (B ) X-ray s/o lytic left scapular lesion. (C ) MRI sagittal view of left scapula. (D ) MRI axial view of left scapula. MRI, magnetic resonance imaging.
An X-ray shoulder ([Fig. 1B ]) followed by plain and contrast magnetic resonance imaging (MRI; [Fig. 1C, D ]) conducted at our institute revealed a 66 × 86 × 83 mm mass with altered signal intensity and post-contrast enhancement within the blade of the left scapula, along with a large extra-osseous soft tissue component on its posterior aspect. Multiple areas of necrosis and hemorrhage were noted. No loco-regional metastasis was detected in the scan. The imaging features suggested an aggressive bone neoplasm, with Ewing's sarcoma as the provisional diagnosis.
Positron emission tomography-contrast-enhanced computed tomography (CT) showed FDG uptake in a destructive lytic lesion of the left scapula with the involvement of skin and adjacent muscles. The left lower lobe lung lesion also showed mild FDG uptake suggestive of infective etiology.
The patient was found to have thrombocytopenia with an abnormal coagulation profile. ([Table 1 ]). A J-needle biopsy was performed under general anesthesia following a platelet transfusion. The pathology report identified a capillary hemangioma. The case was discussed in our multidisciplinary team meeting, and a diagnosis of Kasabach–Merritt syndrome was made.
Table 1
Hematological parameters and coagulation profile throughout the treatment and follow-up phase
Platelet count
(150–450 109 /L)
Hb (g/dL)
WBC
(4.5–11 × 109 /L)
PT
(10–15 s)
aPTT
(23–33 s)
INR
(0.8–1.3)
At presentation
18
10.7
11.5
12.3
40.7
1.07
After initiation of steroids + propranolol
25
10.6
17
14.8
38
1.3
Post 1 cycle of VCR
45
10.2
12.6
13.6
37
1.2
Post 2 cycles of VCR
33
10.6
28
14.3
34.6
1.22
Pre-embolization
18
10.3
20
12.2
38.9
1.02
Post-embolization
200
9.9
14.6
11.9
26.6
0.99
Pre-op
247
9.2
10.6
11.2
28
1.1
POD 1
204
10.6
11.1
10.4
27.4
1.02
POD 3
409
11.1
10
9.4
30.2
0.8
POD 15
506
11.4
12
11
28.6
0.9
6 monthly F/U
363
13.4
13
12.4
33
1.01
Abbreviations: aPTT, activated partial thromboplastin time; F/U, follow-up; Hb, hemoglobin; INR, international normalized ratio; PT, prothrombin time; WBC, white blood cell.
Initial medical management included steroids and β-blockers. However, due to persistent low platelet counts, the patient was started on weekly Vincristine and received two cycles before surgery. Although the platelet count remained low, it was stable during chemotherapy.
Preoperatively, the patient underwent angio-embolization with PVA (polyvinyl alcohol) particles due to the high-risk nature of the surgery, given the large mass and increased risk of bleeding. By Day 2 post-angio-embolization, the platelet counts returned to normal ([Table 1 ]). A compression bandage was also applied. There was an initial transient reduction in tumor size, but it increased again in the following week.
Consequently, the patient was scheduled for surgical intervention and underwent a total scapulectomy (Type 3 Tikhoff–Linberg classification). The patient was positioned in the right lateral position. An elliptical incision ([Fig. 2A ]) was made, encompassing the tumor and the involved blackened skin, extending from the acromion tip superolaterally to the left paravertebral region inferomedially. All muscle attachments of the scapula were divided. Bony cuts were made at the acromion and coracoid processes. The glenohumeral joint was dislocated by cutting the capsule, and the specimen was removed ([Fig. 2B ]). The shoulder joint capsule was repaired, a negative suction drain was inserted, and the wound was closed primarily. Shoulder immobilization was advised for 6 weeks. Postoperatively, steroids were tapered and eventually stopped.
Fig. 2 (A ) On table positioning with proposed elliptical skin incision. (B ) Final specimen. (C ) Section shows vascular channels invading the bony cortex. (D ) X-ray left shoulder AP view at 6 months follow-up. AP, anteroposterior.
A gross pathological examination of the cut section revealed a circumscribed solid friable mass with extensive hemorrhage and necrosis. All margins were wide and free of tumors. Microscopic examination showed a tumor composing of variably sized, dilated, thin- and thick- walled vessels lined by a single layer of endothelial cells. Vascular spaces were separated by fibrous septa. No cellular atypia/mitosis was identified. The tumor involved scapular bone and deltoid muscle. Final histopathological diagnosis favored cavernous hemangioma of scapula ([Fig. 2C ]). Patient was followed up with X-ray ([Fig. 2D ]) after 6 months. No evidence of recurrence was found.
Discussion
Hemangioma of the scapula is an uncommon benign vascular tumor. Its presentation along with consumptive coagulopathy and thrombocytopenia (Kasabach–Merritt syndrome)[4 ] is an extremely rare manifestation of the disease which poses a substantial challenge in the management of patients.
To the best of our knowledge, no such case has been documented in the literature till date. Thus, the exact etiology remains unclear.
Histologically, hemangiomas can be of either capillary or cavernous types. Capillary hemangiomas consist of numerous torturous small vascular channels lined with epithelium, while the more common cavernous hemangiomas present with large dilated vessels lined with a single layer of endothelial cells surrounded by a fibrous stromal layer.[5 ] In general, hemangiomas have a good prognosis with very low recurrence rates.[6 ] Although hemangiomas of the scapula are extremely rare, they should be considered as differential diagnoses of all scapular tumors. The differential diagnosis may include malignant scapula tumors, such as chondrosarcoma, Ewing's sarcoma, and myeloma or benign scapula tumors that included fibrous dysplasia, osteochondroma, eosinophilic granuloma, and aneurysmal bone cysts.[7 ]
CT and MRI scans reveal the extent of tumor and cortical destruction more clearly. The presence of fat density on MRI examinations, well-defined rather than infiltrative borders, sclerotic margins, and a honeycomb appearance[3 ] are highly suggestive of bone hemangiomas. Ching et al reported that bone hemangiomas commonly exhibit hypo-intensity on T1-weighted images and hyper-intensity on T2-weighted images depending on the quantity of vascularity and adipose tissue.[3 ] Therefore, it is crucial to evaluate every radiological abnormality and to carefully assess any suspicious features of malignancy before labeling the lesion as a benign entity.
Asymptomatic patients with small tumors can be managed conservatively since the vascular tissue in hemangioma gets replaced by fibrous tissue leading to self-healing. However, symptomatic patients or those with large tumors who are at increased risk of pathological fractures due to expansive nature of swelling should be offered some form of intervention.[8 ] These may include angio-embolization, microwave ablation, radiotherapy, or surgery depending on the site and extent of these lesions. Special attention has to be given to patients presenting with consumption coagulopathy since they are at increased risk of catastrophic bleeding either before or during surgery. These patients require a multimodality treatment approach while planning for resection and potential cure.
Kasabach–Merritt syndrome shows wide variation in its response to different treatment modalities. These include external compression, angio-embolization, use of steroids, interferon-α, sclerotherapy, chemotherapy, radiation, or surgery.[4 ] Currently, there are no defined treatment guidelines regarding the indications and timing of using these above-mentioned modalities.
In our clinical practice, we often see patients of Kasabach–Merritt syndrome responding well to steroids within few days of initiation of therapy. One-third of the patients however may be steroid-resistant (as in this case). In those patients, the use of Vincristine weekly is a safe and effective treatment strategy owing to the angiogenic nature of the tumor.[9 ] Enjolras and colleagues found the response rate to chemotherapy was 100% after 22 weeks of chemotherapy.[10 ] In the present case, completion of the chemotherapy regimen was not possible since the response became static after two cycles and progression occurred in the size of the lesion. Therefore, the patient was taken up for surgical excision, which is the only feasible treatment modality that can provide cure in considerable number of cases.
Conclusion
An accurate diagnosis is essential for surgical management of bony hemangioma. It becomes difficult to identify such lesions even with CT/MRI owing to the bony destruction and expansile nature of the lesion which mimics aggressive bony tumors. Histological evidence therefore helps to establish diagnosis. The importance of detailed history and examination with due consideration of age at presentation, site, size, and characteristics of tumor (clinically and radiologically) to arrive at a diagnosis cannot be overemphasized.
The current case report analyses the clinical and imaging features of scapular hemangioma presenting with consumptive coagulopathy and highlights few of the possible diagnostic and management methods mentioned in the literature. The results indicate that a careful evaluation of clinical and radiological abnormalities is crucial to prevent misdiagnosis and overtreatment. Furthermore, this study may increase the clinical awareness regarding the rare presentation of hemangioma of bone with even rarer manifestation in the form of Kasabach–Merritt syndrome.
