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Kaposiform hemangioendothelioma (KHE) is a rare, locally invasive vascular tumour of childhood that may occur in soft tissue or bones, and is associated with cutaneous plaques and Kasabach-Merritt phenomenon (KMP). We present an instance of a 9-year-old girl with primary vertebral involvement of KHE, whose clinical presentation was with painless, progressive scoliosis alone, sans cutaneous markers. We highlight the imaging features of this rare manifestation and importance of histopathological diagnosis for optimal management.
Kaposiform hemangioendothelioma (KHE) is a rare vascular tumour of childhood that commonly occurs in the trunk, retroperitoneum, extremities and occasionally in the head and neck.
in 1993, it has since been differentiated from juvenile hemangioma. KHE commonly appears as a cutaneous purple, indurated plaque either at birth or in early childhood,
Thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon) is associated with Kaposiform hemangioendothelioma and not with common infantile hemangioma.
and though non-metastasizing, can be locally invasive. Imaging plays critical role in the diagnosis, prognostication and also for surgical planning in patients with spinal KHE. There are few mimics of KHE which can be distinguished by imaging and will be highlighted in this case report along with the review of literature.
2. Case report
A 9-year-old female presented to the orthopaedic OPD with progressive scoliotic deformity of her back, first noticed one year ago. There was no complaint of back pain, radiculopathy, sensorimotor or bowel and bladder disturbance. The absence of fever, weight loss or constitutional symptoms in the past was also noted. She was the first-borne child of a nonconsanguineous union, with an uneventful full-term birth. Her activities of daily living were unaffected. Menarche had not been attained at time of presentation.
On physical examination, thoracic scoliosis with convexity to left was seen. Her right shoulder was positioned higher, with prominence of right scapula on upright position, enhanced on performing Adam's forward bending test. Ligamentous laxity was elicited with a Beighton score of 8. Neurological examination was unremarkable. No neurocutaneous markers or external stigmata of spinal dysraphism. Hemogram showed anaemia with haemoglobin of 9.8 g/dL. Other laboratory parameters were within normal range. Spine radiography revealed left thoracic scoliosis with involved vertebrae and ribs showing lysis-sclerosis, ill-defined margins and variable degrees of collapse. Apex of scoliosis was at T7 vertebra. Cobbs angle of 50° was seen between T6 and T9 on standing; corrected to 35° on spine traction (Fig. 1). An MRI of spine showed T1 hyperintense/T2 isointense lesions entirely occupying anterior and posterior elements of all thoracic vertebrae, and multiple bilateral ribs (Fig. 2, Fig. 3). Similar lesions were also seen in the bodies of L3 and S1 vertebrae. CT showed destruction of secondary trabeculae within these vertebrae with diffusely reduced bone density (Fig. 4). The spinal cord was normal, with no neuraxial abnormality. Taking into consideration the patient's symptomatology and imaging, a preliminary diagnosis of multiple vertebral and rib vascular malforamation contributing to thoracic scoliosis was made. A clinical suspicion of possible Gorham's disease was also raised. There was no evidence of soft tissue component in MRI scan and no evidence of cortical destruction as seen in CT scan performed during biopsy.
Fig. 1Supine frontal radiograph with application of axial traction. Multilevel vertebral lucent-sclerosis, collapse and resultant left thoracic scoliosis with apex at T7 vertebra seen.
Fig. 2a,b: Sagittal a) T1W and b) T2W images of cervical and upper thoracic spine show hyperintense marrow replacement of upper thoracic vertebrae (white arrows).
Fig. 3a–c: Sagittal a) T1W, b) T2W and c) Short Tau Inversion Recovery (STIR) images of thoracolumbar spine showing hyperintense marrow replacement of multiple thoracic, lumbar and sacral vertebrae.
Fig. 4Curved reformatted coronal CT image of whole spine. Scoliosis with curvature to left from T6 to T9 levels seen (delimited by white arrows), with osteopenia, lysis-sclerosis and prominent primary trabeculation within multiple vertebrae (yellow arrows).
A vertebral biopsy was performed under CT guidance, sampling lesions from T7 vertebral body and pedicle, and L3 vertebral body, which revealed a vasoformative neoplasm. Open biopsy was thus considered, which was performed in concert with application of growth rods due to the large magnitude of scoliotic curvature at presentation and the individual's skeletal maturity portending the future onset of growth spurt and worsening deformity. Pedicle screws were placed bilaterally at T2, T3, T12 and L1 levels and on the left at T4. Contoured rods were attached to the end instrumented vertebrae and distraction was performed. Multiple biopsies were taken subsequently. The samples obtained thus were subjected to histopathological examination, which revealed trabecular bone with intervening vascular proliferative lesion displaying rounded and confluent glomeruloid areas, thin-walled capillary-sized blood vessels and cavernous vascular spaces. Positive stains were obtained for CD34 and ERG (ETS-related gene), suggesting endothelial origin (Fig. 6). Post-operatively, the child was discharged and advised follow-up after 4 weeks (Fig. 5).
Fig. 5Frontal radiographs of thoracic spine in a) Immediate post-operative and b) 7-month follow-up phase. Implants are seen to be retained in normal position, with non-progression of osteolysis.
Fig. 6Photomicrographs of a) Hematoxylin/Eosin stain of vertebral biopsy sample shows vascular proliferative lesion with glomeruloid areas, thin-walled blood vessels and cavernous vascular spaces, b) CD34 and c) ERG positive stains suggesting endothelial origin.
KHE is a rare, locally aggressive tumour of endothelial-derived spindle cell origin that occurs in childhood, with approximately half of all cases presenting at birth.
Thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon) is associated with Kaposiform hemangioendothelioma and not with common infantile hemangioma.
When involving the muscles, joints or vertebrae, joint contractures, muscle atrophy, subluxations, impaired mobitility and scoliosis may result, the latter due to destruction of endplates leading to ipsilateral growth arrest and vertebral collapse.
Scoliosis may also be seen with paraspinal soft-tissue lesions, where production of pro-fibrotic agents by the tumour causes soft tissue contracture and spinal curvature.
Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 13-2004. A newborn girl with a large cutaneous lesion, thrombocytopenia, and anemia.
Very few cases have described a concurrence of vertebral involvement by the lesion, association with scoliosis and absence of characteristic skin lesions: so far, 23 cases of KHE involving bone have been described,
of which 13 were in the spine, 6 presented with scoliosis and only 2 presented with scoliosis without cutaneous manifestations (Table 1). Lisle et al. reported a case of KHE involving multiple thoracolumbar vertebrae without skin changes or scoliosis.
Both were treated via posterior instrumentation and fusion, with satisfactory arrest of scoliosis progression. Qiu et al. described a series of cases of painful scoliosis with limited range of movement, with involvement of thoracolumbar vertebrae, ribs, ilium and femur.
Our patient presented with painless scoliosis with no restriction of movement or neurological abnormality.
Table 1Literature review of reported cases of Kaposiform Hemangioendothelioma (KHE) presenting as scoliosis. CT - Computed Tomography, STIR - Short Tau Inversion Recovery.
Radiographically, KHE may show diffuse lucency and/or sclerosis of affected vertebrae and multiple ribs, with variable degrees of vertebral collapse and scoliosis. On MRI, lesions of soft-tissue origin show local invasion and traverse multiple tissue planes, and are iso-to-hypointense on T1W and hyperintense on T2W and fat-suppressed sequences. Administration of gadolinium causes avid homogeneous enhancement.
signal on T2W can also be seen (the latter may be explained by intralesional hemorrhage obscuring its native appearance). Available literature on KHE involving the spine has described the CT appearance as a soft-tissue mass in the paravertebral region, showing erosion and lytic-sclerotic change in adjacent vertebrae. One instance reports intravertebral KHE showing lysis-sclerosis of vertebral bodies, similar to our case.
Important differential diagnoses include spinal Gorham-Stout syndrome (GSS), generalised lymphatic anomaly, systemic causes of osteopenia such as rickets and metastatic neoplasm (i.e., neuroblastoma). Spinal GSS results in intraosseous lymphatic malformations that present with progressive cortical-predominant osteolysis (cf. medullary osteolysis with KHE)
of appendicular skeleton, with a significant infiltrative soft-tissue component. However, it is uncommon for GSS to involve the axial skeleton, and presents with kyphoscoliosis if so. Generalised lymphatic anomaly (GLA) involves multiple organs and is rarely limited to bone, and is associated with pleural and pericardial effusions, mediastinal mass, splenic cysts and lymphedema. Both of these entities appear similar to KHE on imaging (T1 and T2 hyperintense lytic vertebral lesions), and the presence of ancillary features may help in their distinction from KHE.
Systemic causes of osteopenia such as rickets may be assessed through blood investigations and characteristic radiographic appearance of long bones.
Experience with managing KHE is limited owing to the rarity of the lesion. An early biopsy and histopathological confirmation are important. Due to its locally invasive nature, complete excision is ideal
; however, when present in complex anatomic locations, this may not always be possible. It has been seen that posterior instrumentation with fusion may be sufficient to arrest the progression of scoliosis, in the absence of complete excision.
Thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon) is associated with Kaposiform hemangioendothelioma and not with common infantile hemangioma.
; transarterial embolisation may be performed in these cases.
In our case, rapidly progressive spinal curvature was the presenting complaint, and initial clinical presumption was idiopathic scoliosis. The difficulty in diagnosis of KHE in the absence of cutaneous markers and laboratory parameters suggestive of thrombocytopenia or coagulopathy related to KMP. Additionally, the implicated lesions were vertebral in location and hence clinically inaccessible. The suspicion of idiopathic scoliosis was tenuous as the subject had not attained puberty. Upon imaging, the initial differential diagnoses were multiple vertebral hemangiomas and Gorham's disease. The hyperintensity on T1W sequences diminished the possibility of metastasis or infection. Hence, imaging and histopathology played a central role in the diagnosis of the etiology of her scoliosis.
Due to the non-progression of KHE beyond the age of approximately ten years, posterior spinal instrumentation and deformity correction was deemed an appropriate surgical intervention. In contrast, due to the progressive osteolysis seen with GSS, placement of screws would result in loosening and implant failure. On 7-month follow-up post surgery, the patient was complaint-free and implants were seen to be normally positioned.
4. Conclusion
Extensive spinal vascular malformation and resultant scoliosis is rare. Differential diagnosis for such diffuse bone changes includes Gorham-Stout syndrome (GSS), generalised lymphatic anomaly, systemic causes of osteopenia such as rickets and metastatic neoplasm (i.e., neuroblastoma). While metabolic and metastatic pathologies can be easily diagnosed based on clinical and radiological findings, differentiating GSS and KHE can be changing yet important. Key radiological features and histopathology are critical for differentiating these entities for surgical management and prognostication.
Author contribution
All the authors have contributed towards study design, data acquisition, analysis, interpretation along with drafting, review and final approval of article.
Conflicts of interest statement and funding
No conflict of interest.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
None.
References
Gruman A.
Liang M.G.
Mulliken J.B.
et al.
Kaposiform hemangioendothelioma without Kasabach-Merritt phenomenon.
Thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon) is associated with Kaposiform hemangioendothelioma and not with common infantile hemangioma.
Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 13-2004. A newborn girl with a large cutaneous lesion, thrombocytopenia, and anemia.
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