We retrospectively reviewed fine-needle aspiration biopsy (FNAB) specimens of 301 soft tissue lesions of the extremities and trunk. Final diagnoses were 137 benign and 86 malignant neoplasms and 78 nonneoplastic lesions. Of the 301 FNAB samples, 279 (93%) were adequate for cytologic diagnosis. The adequate FNAB specimens were initially grouped into three broad categories: benign (197 cases), malignant (57 cases), and suspicious for malignancy (25 cases). Sensitivity and specificity for diagnosis of a malignant lesion were 92% and 97%, respectively. The specimens were cytomorphologically classified into nine categories: small round (14 cases), spindle cell (77 cases), epithelioid/polygonal (16 cases), pleomorphic (29 cases), myxoid (19 cases), lipomatous (37 cases), epithelial (23 cases), inflammatory lesions (28 cases), and others (36 cases). Specific FNAB diagnoses were correct in 151 of 279 cases (54%) in combination with clinical and radiologic findings. FNAB is a valuable technique for the primary diagnosis of soft-tissue lesions.

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667ntraosseous gas collection is observed in various disorders. A pneumatocyst is a rare, gas-containing lesion in the bone. This condition is most frequently encountered in the ilium and the sacrum, adjacent to the sacroiliac joints [1]. Pneumatocysts in the cervical spine are rarely seen. The natural course of pneumatocysts is obscure. We report a case of a cervical intraosseous pneumatocyst in association with degenerative disk disease. The pneumatocyst radiologically changed to a fluid-filled cyst and was subsequently replaced by granulation tissue. To our knowledge, the radiologic phenomenon has never been described in the English-language literature. Case ReportA 56-year-old woman consulted an orthopedic unit complaining of neck pain and stiffness of 6 months' duration. Standard radiographs of the cervical spine revealed an osteolytic lesion in C5. Metastatic bone disease in the cervical spine was suspected, and the patient was referred to the Rokko Island Hospital. On physical examination, mild tenderness to palpation was noted over both cervical paravertebral muscles. Only mildly decreased touch sensations were present over the C7 dermatome on the left side. Other neurologic findings were normal.An anteroposterior radiograph of the cervical spine revealed a small round focal radiolucent lesion in the C5 vertebral body. Lateral radiographs revealed degenerative disk disease at the C5-C6 and C6-C7 levels, with narrowed disk spaces and deformed vertebral bodies (Fig. 1A). An oblique radiograph of the cervical spine clearly showed the radiolucent lesion in the C5 vertebral body (Fig. 1B). The patient subsequently underwent MR imaging, CT, and 99m Tc scintigraphy to evaluate the lesion. Sagittal T1-and T2-weighted MR images showed a small homogeneous hypointense lesion in the C5 vertebral body adjacent to the C5-C6 intervertebral disk (Fig. 1C). Axial T1-and T2-weighted MR images showed a hypointense lesion located in the posterolateral region of the C5 vertebral body to the right of the midline. The lesion was not enhanced on contrast-enhanced T1-weighted images (Fig. 1D). CT revealed a round, well-circumscribed lesion, 6 mm in diameter and with gas attenuation, in the C5 vertebral body (Fig. 1E). The CT attenuation at the epicenter of the lesion was -890 H, suggesting a collection of gas. No evidence was seen on CT or MR images of communication of the lesion with the disk space or the spinal canal. 99m Tc scintigraphy revealed increased isotope uptake in C5 and C6, which is concordant with degenerative disk disease. The imaging findings excluded metastatic bone disease of the cervical spine, and an intraosseous pneumatocyst was diagnosed.The patient was treated for the degenerative disk disease with antiinflammatory agents, which alleviated the symptoms. Radiographs obtained 10 weeks after the initial presentation revealed complete disappearance of the pneumatocyst in C5. Follow-up CT scans obtained 14 weeks after the initial presentation revealed a cystic structure in the C5 vertebral body (Fig. 1F). The ...

Osteoblastomas located on the surface of the cortical bone, so-called periosteal osteoblastomas, are extremely rare. We report on a case of periosteal osteoblastoma arising from the posterior surface of the right distal femur in a 17-year-old man. Roentgenographic, computed tomographic, magnetic resonance imaging, and histologic features of the case are presented. Periosteal osteoblastoma should be radiologically and histologically differentiated from myositis ossificans, avulsive cortical irregularity syndrome, osteoid osteoma, parosteal osteosarcoma, periosteal osteosarcoma, and high-grade surface osteosarcoma. Although periosteal osteoblastoma is rare, this tumor should be included in the differential diagnosis of surface-type bone tumors.