Multiple unexpected lesions of metachondromatosis detected by technetium-99m methylene diphosphonate SPECT/CT: A case report.

RATIONALE: Metachondromatosis (MC) is a very rare genetic disease, which is infrequently reported worldwide, which leads to osteochondroma and enchondromatosis. The disease has been shown to be associated with loss of function of the tumor suppressor gene "protein tyrosine phosphatase, non-receptor type 11" (PTPN11). PATIENT CONCERNS: A 12-year-old female was admitted to the hospital with pain due to an enlarged mass in her left fifth finger. DIAGNOSIS: Examination of the left hand by computed tomography (CT) revealed an expanding type of round and low-density lesion in the fifth proximal phalanx. The patient then underwent technetium-99m methylene diphosphonate single-photon emission CT/CT (Tc-MDP SPECT/CT) to assess the nature of the lesion. The SPECT/CT image revealed dilated osteopathy and increased activity of the fifth proximal phalanx on the left hand. Unexpectedly, the examination of the right hand revealed slight expanded lesions and increased activities of the third metacarpal and proximal phalange, as well as the fourth proximal phalange and the middle phalanx. On the basis of the patient's symptoms and the results of the above-mentioned examinations, we diagnosed the patient as having MC in her hands. INTERVENTION: Considering the pain of the fifth finger of the left hand, the patient underwent debridement of the fifth proximal phalanx of the left hand and internal fixation with bone graft taken from the body. OUTCOMES: The patient was discharged after a week of observation. One year later, she was admitted to the hospital again for removal of the bone healing internal fixation after osteoma surgery. Preoperative Tc-MDP SPECT/CT revealed that the left-handed lesions displayed postoperative changes, while the multiple lesions in the right hand increased in volume but remained unchanged in number. LESSONS: This case revealed the CT and Tc-MDP SPECT/CT imaging features of MC. Specifically, SPECT/CT imaging contributed to the diagnosis of clinically asymptomatic bone lesions, and the 3D SPECT/CT fusion allowed a more comprehensive and intuitive view of the lesion by combining anatomy and function.

Otofaciocervical syndrome and metachondromatosis in a girl: Presentation of a novel association and remarks on clinical variability of branchial-arch disorders.

Otofaciocervical syndrome (OFCS) is a rare disorder characterized by facial, ear, branchial, and musculoskeletal anomalies, along with hearing loss and mild intellectual disability. Clinically, its distinction from branchiootorenal syndrome can be difficult. To date, the coexistence of OFCS and metachondromatosis has not been reported. Here, we describe a sporadic patient with both OFCS and metachondromatosis. This novel association prompts us to do some remarks on the clinical variability of branchial-arch disorders; in fact, our observations are consistent with the highly variable expressivity of OFCS and illustrate the need of a more accurate characterization of these branchial-arch disorders. In the meantime, involvement of clavicles, scapulae and shoulders remains a distinctive feature of OFCS.

Genochondromatosis type I: A clinicoradiological study of four family members.

Genochondromatosis is an extremely rare autosomal dominant disorder, which manifests during childhood and tends to regress in adult life. The bony lesions are symmetrically distributed with characteristic localization at the metaphysis of proximal humerus and distal femur. Two types have been described based on the involvement of clavicle. Usually asymptomatic, sometimes patients may present with pathological fractures. In this communication, we describe four members of a family with Genochondromatosis type I, with some additional clinical and radiological findings not reported previously.

Extra- and intra-articular synovial chondromatosis and malignant transformation to chondrosarcoma.

Intra- and extra-articular primary synovial chondromatosis (SC) was observed in a five-year-old, entire male German Shepherd. Thousands of small cartilaginous nodules were removed from the stifle joint as well as from several adjacent muscles. Diagnosis of SC was established based on clinical, radiographic and biopsy results. The owner declined to have a new surgery performed for complete nodule removal and partial synovectomy. Nine months after the initial presentation, a proximal pathological intra- articular tibial fracture was observed and malignant transformation to chondrosarcoma was diagnosed after limb amputation. No metastasis was observed after 1.5 years of follow-up.

Clinical usefulness of thallium-201 scintigraphy and magnetic resonance imaging in the diagnosis of chondromyxoid fibroma.

Chondromyxoid fibroma (CMF) is a benign bone tumor. However, it is sometimes difficult to distinguish this tumor from chondrosarcoma. We report a rare case arising from the proximal fibula, presenting multimodality imaging features. An 18-year-old man presented with a 2-year history of gradually increasing pain and swelling in his left knee. Radiograph showed an area of osteolysis with lobulation. Magnetic resonance (MR) imaging demonstrated that almost the whole lesion was enhanced with Gd-DTPA. Scintigraphy examination with (99m)Tc-biphosphonate showed strong accumulation in the periphery. On Ga-67-citrate scintigraphy, there was a little uptake. Thallium-201 scintigraphy showed strong accumulation of the whole lesion in early and late scans. The tumor was diagnosed as CMF by open biopsy. It is important that CMF is correctly distinguished from other tumors because this may be histologically overdiagnosed as chondrosarcoma. Contrast-enhanced MR imaging and thallium-201 scintigraphy may be useful to distinguish CMF from benign bone tumors or chondrosarcoma.