Osteochondromas around the ankle: Report of a case and literature review

INTRODUCTIONAn osteochondroma or exostosis is a benign bone tumour consisting of a bony outgrowth covered by a cartilage cap that occurs commonly in the metaphysis of long bones, mainly the distal femur, proximal tibia and proximal humerus.PRESENTATION OF CASEWe describe an unusual case of a distal tibia osteochondroma affecting the lateral malleolus of a young girl.DISCUSSIONMost osteochondromas are asymptomatic and seen incidentally during radiographic examination. Osteochondromas are rarely localized in the foot and ankle.CONCLUSIONAlthough most of the osteochondromas in children should be treated conservatively until skeletal maturity, those affecting the distal tibia or fibula should be treated with surgical excision in order to prevent ankle deformity, syndesmotic lesions or even fracture due to the expanding nature of this benign tumour.     

A giant subungual exostosis perforating through skin of the toe

Subungual exostosis is typically an uncommon, benign, bony tumor of cartilaginous bone that usually occurs as a solitary, solid lesion under the nail of the first toe or the fingernail. It may be difficult to diagnose subungual exostosis from a clinical presentation and it should be confirmed by radiographic examination. The treatment is surgical excision. It is essential to see normally cancellous bone under the area of excision to ensure that the tumor does not recur. In this article, our goal is to present a subungual exostosis case of the first toe, detailing diagnosis, pathologic findings and surgical management.     

Role of FGF9 and FGF receptor 3 in osteochondroma formation

Osteochondromas are chondro-osseous protuberances that occur in metaphyses of long bones. The cartilaginous cap is assumed to be responsible for the growth of the lesions during childhood and adolescence, but mitotic figures are rarely seen in the cap. Therefore, another cell population, probably mesenchymal cells, is responsible for proliferation and growth. Residual mesenchymal cells capable of rapid proliferation are difficult to detect due to lack of specific histologic features. Two specific markers for mesenchymal cells, FGF receptor 3 (FGFR3) and collagen type IIa, have been described. Osteochondroma mesenchymal cells are found in the soft tissues overlying the cartilage cap. The surrounding areas of typical cartilage are negative for both mesenchymal cell associated antigens. The soft tissues overlying the cartilage do not have cartilaginous features. The undifferentiated cells overlying the exostosis yield in culture a rapidly proliferating homogenous population of fibroblast-like cells. Expression at the mRNA level of FGF9, FGFR3, and collagen type IIa is found in these cells, but not in skin fibroblasts from afflicted or healthy individuals. Exogenous administration of TGFbeta1 to cultures of hereditary multiple exostosis eliminates FGF9 expression. These results indicate fibrous regions contain the mesenchymal cells responsible for osteochondroma growth.     

Aneurysms of the posterior inferior cerebellar artery-vertebral artery complex: variations on a theme

Aneurysms of the posterior inferior cerebellar artery-vertebral artery complex are relatively uncommon lesions. They include aneurysms at the origin of the posterior inferior cerebellar artery (PICA-VA), aneurysms on the distal artery (PICA) and aneurysms at the junction of the vertebral and basilar arteries (VA-BA). We have had the opportunity to treat 17 patients and study the radiological records of 9 additional patients in the past 8 years. The aneurysms ranged in size from 3 to 30 mm, with mean values of 10.6, 7.3, and 9 mm for PICA-VA lesions, distal PICA lesions, and VA-BA lesions, respectively. Three of the 4 VA-BA aneurysms were located at the midline, and the mean distance of the PICA-VA aneurysms from the midline was 7.6 to 9.4 mm; 2 aneurysms crossed the midline from their parent VA. The aneurysms were located slightly more often on the left side (left:right ratio, 1:2), were found more frequently in women (2.25:1), and occurred at a mean age of 50 years. Ten aneurysms at the origin of the PICA and 4 VA-BA aneurysms were treated via a lateral suboccipital craniectomy; 3 distal PICA aneurysms were exposed by a midline craniectomy. Surgery was carried out acutely in 5 patients. Tortuousness of the VA required contralateral approaches in 2 patients, an exploratory craniectomy in 1 patient, and an approach toward the dome of 1 patient with a VA-BA aneurysm. Morbidity was primarily due to cranial nerve dysfunction. There were no perioperative deaths. These aneurysms can easily be missed on initial radiographic examination; one appeared only on the second study, one was seen to grow over 16 days, and one was discovered at the level of C1 extracranially. Our radiographic and surgical approach to the treatment of these lesions is presented.     

A pediatric case of rupture of the brachial artery and radial nerve palsy secondary to proximal humeral exostosis

Rupture of the brachial artery associated with radial nerve palsy in a context of exostosis of the proximal humerus has not been described to date in the literature. Our patient was a fourteen-year-old girl with a history of violent pain occurring suddenly with no prodrome or triggering factor. The pain was localized at the level of the proximal left humerus. Physical examination revealed the presence of a hematoma and complete motor radial nerve palsy. The diagnosis was not confirmed by computed tomography with contrast injection but was confirmed by magnetic resonance imaging which eliminated malignant transformation of the exostosis. After checking the neurovascular bundles and evacuating the hematoma, treatment consisted in resection of the exostosis and arterial repair with an autologous venous graft. We discuss the diagnostic and therapeutic challenges which present vascular complications due to exostosis.     

Targeted Disruption of Shp2 in Chondrocytes Leads to Metachondromatosis With Multiple Cartilaginous Protrusions

Metachondromatosis is a benign bone disease predominantly observed in the hands and feet of children or young adults demonstrating two different manifestations: a cartilage‐capped bony outgrowth on the surface of the bone called exostosis and ectopic cartilaginous nodules inside the bone called enchondroma. Recently, it has been reported that loss‐of‐function mutations of the SHP2 gene, which encodes the SHP2 protein tyrosine phosphatase, are associated with metachondromatosis. The purpose of this study was to investigate the role of SHP2 in postnatal cartilage development, which is largely unknown. We disrupted Shp2 during the postnatal stage of mouse development in a chondrocyte‐specific manner using a tamoxifen‐inducible system. We found tumor‐like nodules on the hands and feet within a month after the initial induction. The SHP2‐deficient mice demonstrated an exostosis‐like and enchondroma‐like phenotype in multiple bones of the hands, feet, and ribs as assessed by X‐ray and micro‐computed tomography (CT). Histological assessment revealed the disorganization of the growth plate cartilage, a cartilaginous protrusion from the epiphyseal bone, and ectopic cartilage nodules within the bones, which is consistent with the pathological features of metachondromatosis in humans (ie, both exostosis and enchondroma). At molecular levels, we observed an abundant expression of Indian hedgehog protein (IHH) and fibroblast growth factor 2 (FGF2) and impaired expression of mitogen‐activated protein kinases (MAPK) in the affected cartilage nodules in the SHP2‐deficient mice. In summary, we have generated a mouse model of metachondromatosis that includes manifestations of exostosis and enchondroma. This study provides a novel model for the investigation of the pathophysiology of the disease and advances the understanding of metachondromatosis. This model will be useful to identify molecular mechanisms for the disease cause and progression as well as to develop new therapeutic strategies in the future. © 2014 American Society for Bone and Mineral Research.     

遗传性骨软骨瘤软骨细胞的生物学特性

目的:观察遗传性骨软骨瘤软骨细胞的生物学特性。方法:采用透射电镜、细胞培养等方法观察肿瘤软骨细胞形态特征;同时观察肿瘤软骨细胞的增殖、贴附能力,与正常人关节软骨细胞做对照。结果:透射电镜(TEM)发现肿瘤软骨细胞膜附近含有大量的微丝结构,集结成束,与细胞突起有关;体外单层培养发现肿瘤软骨细胞突起增多,细胞呈现星形;骨软骨瘤软骨细胞的增殖与贴附能力随着传代的增加减慢和减低,传4代细胞增殖能力和贴附能力均与肿瘤原代细胞及正常关节软骨细胞具有明显差别(P<0.1)。结论:骨软骨瘤软骨细胞虽然与正常软骨细胞大体相似,但生物学特性存在明显区别:细胞形态改变,微丝增加,细胞增殖与贴附能力等均不同于正常软骨细胞。     

An unusual exostosis presenting as a bunion deformity

A large exostosis was the source of a bunion deformity in a 60-year-old woman. Its unusual clinical and radiographic features were suggestive of a bizarre parosteal osteochondromatous proliferation. However, histologic features were most consistent with a benign osteocartilaginous exostosis.     

Arthroscopic Surgery for Degenerative Rupture of the Ligamentum Teres Femoris

We performed arthroscopic debridement for degenerative rupture of the ligamentum teres femoris in a patient and obtained good results. A 78-year-old woman suddenly developed intense load-bearing pain from the left lumbar to gluteal region, and giving way, without a definitive cause. At presentation, the range of motion of the left hip joint for external rotation was 0°, showing restricted motion. When passive internal rotation was applied at 90° of flexion, intense pain in the left gluteal region was induced. At the initial radiographic examination, there were no abnormal findings in the left hip joint. However, arthroscopic findings showed degeneration in the articular cartilage and labrum but no tear. In addition, degenerative rupture of the ligamentum teres femoris was observed and it was entrapped in the posterior joint space. Using a bipolar radiofrequency scalpel, the entrapped stump of the ligamentum teres was vaporized and excised. The restriction in external rotation of the hip joint observable even under anesthesia was resolved immediately after surgery. Two years after surgery, the patient had regained her preoperative walking ability with the aid of a T cane, and radiographic examination showed no coxarthrosis changes. This case indicates that coxalgia caused by degenerative rupture of the ligamentum teres femoris is also a good indication for arthroscopic debridement.     

Popliteal Artery Thrombosis Secondary to Exostosis of the Tibia

This report describes an exceptional case of popliteal artery thrombosis secondary to exostosis of the superior extremity of the superior tibia in a young adult. Correct diagnosis was made during re-operation for recurrent thrombosis. Surgical treatment consisted of resection of the bony tumor and venous bypass to reestablish arterial continuity. Femoropopliteal vascular complications of exostosis are rare, with most cases involving arterial aneurysms or false aneurysms. Differential diagnosis in our young patient took into account the other causes of popliteal thrombosis: entrapped popliteal artery, adventitious cyst, fibrodysplasia, and juvenile arteriopathy. In patients with major functional disability, operative treatment is recommended to remove the bony abnormality and repair the arterial lesion.     

The articular cartilage after osteotomy for medial gonarthrosis. Biopsies after 2 years in 19 cases.

In 19 consecutive patients with medial gonarthrosis, an arthroscopic examination with a biopsy of the load-bearing cartilage in the medial femoral condyle was undertaken at the same time as a proximal tibial osteotomy. A follow-up arthroscopic biopsy was performed on an average of 2 years after the osteotomy. In 9 knees there was an improvement in the cartilage quality, 8 knees were unchanged, whereas 2 knees had deteriorated. Radiographically, 6 knees had improved, 11 were unchanged and 2 had deteriorated. We found no correlation between cartilage improvement and the clinical and radiographic outcome. Our results confirm that an osteotomy has a beneficial effect on the load-bearing cartilage in the medial femoral condyle.     

A case of multiple cerebral aneurysms caused by cardiac myxoma

A case of neoplastic aneurysm caused by left atrial myxoma is reported. The patient was a 50-year-old woman who has been suffered from occasional vertigo and syncopal attack. She was admitted with a sudden loss of consciousness and cerebellar ataxia on December 1, 1983. Cerebral angiogram revealed multiple aneurysms in the periphery of both middle cerebral arteries and obstruction of the right superior cerebellar artery. Echocardiography displayed a cardiac myxoma in the left atrium. She suddenly died from recurrent cerebral embolism on January 7, 1984. The diagnosis was confirmed by the autopsy. The histopathological examination revealed that the wall of cerebral arteries were destroyed by the tumor cells of myxoma, and it caused cerebral aneurysms. We presented the detail of this case, and discussed about a mechanism and a treatment of neoplastic aneurysms.     

Surgical treatment for an unusual cause of localized bronchiectasis

A 17-year-old girl presented with recurrent episodes of pneumonia related to localized bronchiectasis in the lingula. On computed tomography and magnetic resonance imaging, the cause of this was found to be an inwardly projecting exostosis arising from the left fifth rib. The patient underwent thoracotomy and excision of the exostosis with the affected area of lung. We report here the unusual case of a rib exostosis presenting with localized bronchiectasis.     

Development of a dissecting aneurysm on the vertebral artery immediately after occlusion of the contralateral vertebral artery: A case report

A 49 year old female presented with subarachnoid hemorrhage due to a ruptured dissecting aneurysm on the left vertebral artery (VA). Following an occlusion test, we performed proximal occlusion of the left VA with detachable balloons. However, a dissecting aneurysm on the right VA developed three weeks later. After an occlusion test had showed no change in cerebral blood flow, auditory brain stem response, or neurological status, proximal occlusion of the right VA was performed. The patient has returned to normal life without neurological deficits. Bilateral dissecting aneurysms of the VA are quite common, but de novo VA dissecting aneurysms or enlargement of such aneurysms after occlusion of contralateral VA are rare. This case suggests that hemodynamic stress may be a causal factor in the development of VA dissecting aneurysms. Careful pre- and post-operative neuroradiological examination of the contralateral VA are required in patients under-going VA occlusion for dissecting aneurysms.     

Remodeling of the acetabulum after experimental hip joint dislocation--an animal experiment study of the rabbit

PURPOSE: Little is known about the remodeling potential of the acetabulum after dislocation and relocation of the hip joint. Most clinical data rely on radiographic measurements in a clinical setting, with only few singular reports on histologic changes at the time of surgery. This study was undertaken to examine the remodeling potential of the rabbit acetabulum after different length of hip dislocation and to gain insight into the histology of the remodeling process involved. METHOD: The right knee joint was immobilized in 28 matched New Zealand white rabbits, causing dislocation of the associated hip joint. Assessment of the joint status was made by serial X-rays in a reproducible standardized way, allowing measurement of the Acetabular Index (AI). The untreated left hip joints served as controls in the histologic sections and also allowed to develop an age matched scale of normal acetabular development for radiographic assessment. Dislocation was unsuccessful in 2 rabbits, 9 animals were sacrificed with the joint dislocated, and in 13 animals a closed reduction was performed and maintained in a Petrie type position for 10 days. Reduction was unsuccessful in 4 cases. The reduced group was sacrificed after 4 to 12 weeks, the point of harvesting being determined by no further change in the serial standardized radiographic measurements of the AI. All surgical procedures were done under the supervision of a veterinary surgeon and followed an approved protocol. RESULTS: In the time observed, the normal values of the Acetabular Index drop from 30 degrees to 20 degrees over a time of 3 months. In animals with a dislocated hip the AI increased to 40 degrees, which was completely reversible and reached normal values in 4 weeks, if reposition was done at this time (group A). Later reposition did improve the AI, but compared to normal age matched values, the AI remained elevated (> 30 degrees), demonstrating a residual dysplasia (group B). The histologic sections of the control left joints showed normal hyaline cartilage with physiologic vertical stacking of the cartilage zones. In the dislocated group the vertical stacking was lost, with chondrocytes demonstrating a fibro-cartilaginous metaplasia. There was hypocellularity with loss of nuclear staining. These changes were completely reversed in the group A, but remained in group B. CONCLUSIONS: This study demonstrates that an early reduction will not only allow for a normalisation of the radiographic values, but that the histologic changes as they develop during dislocation can completely be reversed. Long standing dislocation will lead to a permanent tissue metaplasia similar to the one seen in compression testing of joint cartilage, therefore loosing the potential for remodeling. Similar processes may occur in the human situation and the findings here underline the necessity for early reduction to allow for a complete remodeling of the hip joint.     

Two distinctive subungual pathologies: subungual exostosis and subungual osteochondroma

BACKGROUND: The purpose of this study was to present features that differentiate subungual exostosis from subungual osteochondroma. METHODS: We treated 11 patients for subungual masses. All were confirmed by radiographic and histologic evaluations to be subungual exostosis or subungual osteochondroma. The study patients comprised eight female and three male patients with a mean age at presentation of 18.7 years (range 1.5 to 70.9). In the five patients with subungual exostosis, three (60%) had a toe lesion, and two (40%) had a finger lesion. In the six patients with subungual osteochondroma, four (67%) had a toe lesion, and two (33%) had finger lesions. We analyzed the clinical features, including trauma history, the existence of infection before surgery, tumor recurrence, and postoperative nail deformity. RESULTS: In all patients, the lesions presented as an exophytic tumor of the nail apparatus, beneath the nail plate, which varied in size from 0.6 x 0.4 cm to 1.2 x 0.9 cm. Excision of these masses produced useful toes or fingers without pain, a tender scar, or nail deformity. Although nails were deformed preoperatively, they grew back without ridges or cracks within 3 to 5 months postoperatively. There were no recurrences based on clinical and radiographic evaluations, and both tumor types showed characteristic radiographic and histologic differences. CONCLUSIONS: Subungual exostosis and subungual osteochondroma are benign but have distinct osseous pathologies. We concluded that subungual exostosis is clinically, developmentally, radiographically, and histologically distinct from subungual osteochondroma.     

Unusual arterial complications caused by an osteochondroma of the femur or tibia in young patients

In the past 2 years three relatively young patients were treated for a severe arterial complication due to an exostosis of the femur or tibia. A 39-year-old man had occlusion of the femoral artery, a 28-year-old man suffered from a popliteal pseudoaneurysm, and a 14-year-old boy presented with occlusion of his femoral artery while stretching his leg. An exostosis on the course of the femoral or popliteal artery, requires additional examination (duplex ultrasonography and magnetic resonance arteriography) in order to exclude an arterial disorder. If arterial compression by an exostosis is shown, an operative procedure to remove the exostosis should be performed.     

Report of an unusual case of trigger finger secondary to phalangeal exostosis.

Trigger finger is commonly secondary to stenosing tenosynovitis. Space occupying lesions in the tendon bed, although uncommon, may prevent smooth tendon gliding. These include lipoma, anomalous muscle insertions, tumours of the tendon sheath and haemangiomas. We describe a patient who had triggering of the left middle finger at the proximal interphalangeal joint due to an exostosis blocking the flexor tendons gliding. Removal of the exostosis relieved the problem. The clinician must be aware that there are other causes for triggering. These may be identified with pertinent findings in the history and physical examination.     

Extraskeletal osteochondroma of the foot

An extraskeletal osteochondroma is an infrequently encountered benign cartilaginous tumor with a predilection for the hands and feet that usually does not exceed 3 cm in diameter. This diagnosis can be misleading because it bears the same name as the osseous neoplasm more commonly referred to as an exostosis. The authors present an unusual case of a painful enlarging mass in the foot of a 28-year-old man who was later diagnosed as having an extraskeletal osteochondroma measuring in excess of 4 cm. Clinical, radiographic, and magnetic resonance images are provided along with intraoperative and histopathologic figures. There was no sign of recurrence 1 year after surgical excision. A review of the literature regarding this uncommon lesion is also presented.     

Isolated trigeminal sensory loss secondary to a distal anterior inferior cerebellar artery aneurysm: case report

A previously healthy 25-year-old woman suddenly developed right-sided facial numbness and a headache. The neurological examination was within normal limits with the exception of meningismus and right-sided facial sensory loss. A computed tomographic scan and a magnetic resonance imaging study demonstrated an acute hematoma in the right cerebellopontine angle. A 4-vessel cerebral angiogram revealed no abnormalities. Posterior fossa exploration disclosed a large, partially thrombosed, fusiform anterior inferior cerebellar artery aneurysm, which indented the pons at the trigeminal root entry zone. The aneurysm was excised, and the patient made an excellent recovery. She was left with a persistent trigeminal sensory deficit. Anterior inferior cerebellar artery aneurysms are rare lesions that generally present with a cerebellopontine angle syndrome; occasionally, facial sensory loss is also a feature. Isolated trigeminal sensory findings, as illustrated in this case, are extremely unusual in posterior fossa vascular lesions.