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This study investigated the prevalence of each of the four features of patellar tendinosis in asymptomatic athletic subjects undergoing patellar tendon anterior cruciate ligament (ACL) reconstruction.Fifty subjects (39 males and 11 females) undergoing ACL reconstruction using a patellar tendon graft were screened for previous tendon symptoms, training and playing history and had their patellar tendons examined with ultrasound prior to surgery. During surgery, a small piece of proximal posterocentral tendon was harvested, fixed and examined under light microscopy. Histopathological changes were graded for severity.Results demonstrate that 18 tendons were abnormal on light microscopy and 32 were normal. There were no differences between subjects with and without pathology in respect of training, recovery after surgery and basic anthropometric measures. Three tendons were abnormal on ultrasound but only one had proximal and central changes.Tendons showed a consistent series of changes. Tenocyte changes were found in all but one of the abnormal tendons. In all but one of the tendons with increased ground substance there were tenocyte changes, and collagen separation was always associated with both tenocyte changes and increased ground substance. No tendons demonstrated neovascularization.It appears that cellular changes must be present if there is an increase in ground substance, or collagen and vascular changes. Further research is required to confirm these findings.

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Background: Myopericytoma (MPC) is a recently proposed term to describe a group of tumours that originate from perivascular myoid cells and show a range of histological growth patterns. Only a small number of series describing MPC have been reported. MPC is frequently misdiagnosed as a sarcoma. Aims: To document the clinical and histopathological findings of a series of MPCs, to describe the range of growth patterns and morphological spectrum, and to compare MPC with myofibroma (MF). Patients/Methods: Fourteen patients with features of MPC and/or MF were identified from the archival files of the department of anatomical pathology, Royal Prince Alfred Hospital, Sydney, Australia. Results: There were six female and eight male patients. The mean and median patient ages were 37 and 35.5 years, respectively. The tumours were located in the skin, subcutis, or superficial soft tissues of the distal extremities (13 patients) or the head and neck region (one patient), and showed a spectrum of morphological appearances. They were divided into two groups based upon the predominant growth pattern corresponding to MPC (seven cases) and MF (seven cases). The feature most suggestive of MPC was the presence of a concentric perivascular arrangement of plump spindle shaped cells. The presence of a zonation/biphasic appearance was most characteristic of MF. Conclusions: MPC exhibits a spectrum of growth patterns that overlap with MF. Tumours can be designated as MPC or MF depending on the predominant growth pattern.

Objectives-Jumper's knee causes significant morbidity in athletes of all standards. However, there are few reference data on the clinical course of this condition in a large number of patients, and the aim of this study was to rectify this. Methods-A retrospective study of the course of jumper's knee in 100 athletes who presented to a sports medicine clinic over a nine year period was carried out. Subjects completed a questionnaire designed to collect details of sport participation, symptoms, and time out of sport. Ultrasonographic results were recorded from the radiologists' reports. Histopathological results were obtained for patients who had surgery. Results-Forty eight subjects recalled that symptoms of jumper's knee began before the age of 20 years. Symptoms prevented 33 from participating in sport for more than six months, and 18 of these were sidelined for more than 12 months. Forty nine of the subjects had two or more separate episodes ofsymptoms. Ultrasonography showed a characteristic hypoechoic region at the junction of the inferior pole of the patella and the deep surface of the patellar tendon. Histopathological examination showed separation and disruption of collagen fibres on polarisation light microscopy and an increase in mucoid ground substance consistent with damage of tendon collagen without inflammation.Conclusions-Jumper's knee has the potential to be a debilitating condition for a sports person. About 33% of athletes presenting to a sports medicine clinic with jumper's knee were unable to return to sport for more than six months. (BrJ Sports Med 1997;31:332-336)

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Intra-osseous hibernoma is a rare cause of sclerotic bone lesions, predominating in the axial skeleton of middle-aged and elderly adults. They have a non-aggressive appearance on CT and on MRI are T1 hypointense to subcutaneous fat and hyperintense to skeletal muscle. They are usually T2 hyperintense and may show peripheral contrast enhancement. They may show increased glucose avidity on FDGPET and may or may not be positive on isotope bone scans. We suspect that with ever-increasing use of a variety of imaging techniques, particularly in a setting of staging for malignant disease, more such cases will come to light. This diagnosis should be added to the differential diagnosis of sclerotic bone lesions.

Dendritic fibromyxolipoma (DFML) is an uncommon, recently described, benign soft tissue lesion that shares many clinical and pathological features with myxoid variants of spindle cell lipoma (SCL). As described, DFML is distinguished from SCL by the presence of dendritic cytoplasmic processes, abundant keloidal collagen and a prominent, often plexiform vascular pattern. We describe the first known reported case of an intramuscular DFML that occurred in the right shoulder region of a 73-year-old man. The tumor displayed the typical histopathological features of DFML but also included foci of chondroid metaplasia, a previously unreported finding. This report also discusses the differential diagnosis, particularly distinguishing DFML from SCL and myxoid liposarcoma. In view of the similarities in many clinical and pathological features between SCL and DFML, we speculate that DFML probably represents an unusual variant of myxoid SCL.