Neoplastic and Non-neoplastic Soft Tissue Lesions Around the Knee.

Neoplastic and non-neoplastic soft tissue masses around the knee are often incidental findings. Most of these lesions are benign with typical imaging characteristics that allow a confident diagnosis. However, some of these incidental neoplastic masses are characterized by morbidity and potential mortality. This review highlights the typical aspects of these lesions, facilitating a correct diagnosis.

Osteomyelitis of the pubic symphysis caused by methicillin-resistant Staphylococcus aureus after vaginal delivery: a case report and literature review.

BACKGROUND: Osteomyelitis of the pubic symphysis is a rare cause of pelvic pain after delivery, mainly caused by Staphylococcus aureus and Pseudomonas aeruginosa. The clinical context is the same as the more common diastasis of the pubic bone, but the presence of intense local pain in association with fever should prompt further clinical work-up based on blood chemistry, microbiology and diagnostic imaging. We report the first case of methicillin-resistant Staphylococcus aureus osteomyelitis of the pubic symphysis occuring after the delivery. CASE PRESENTATION: A 39-year-old woman developed pain over the pubic bone 12 h after the delivery. After 72 h fever rose and laboratory examination showed elevation of C-reactive protein and procalcitonin levels. Pelvic x-rays and magnetic resonance showed pubic diastasis, joint effusion, tiny irregularities of articular surfaces and, severe bone edema. The patient was started on broad spectrum intravenous (IV) antibiotics (piperacillin-tazobactam) and then replaced to IV vancomycin and oral levofloxacin based on antibiogram result. She was then discharged with oral antibiotic therapy and fully recovered. CONCLUSIONS: Due to the rarity of this disease, we compared our experience with the other cases of osteomyelitis of pubic symphysis occurring in peri-postpartum reported in the literature. The course of osteomyelitis was favourable in all patients, and only in one case an additional orthopedic procedure for symphysis fixation was necessary. Knowledge of this rare condition is important to enable prompt diagnosis and treatment.

Concentrated adipose tissue infusion for the treatment of knee osteoarthritis: clinical and histological observations.

PURPOSE: Osteoarthritis (OA) is characterized by articular cartilage degeneration and subchondral bone sclerosis. OA can benefit of non-surgical treatments with collagenase-isolated stromal vascular fraction (SVF) or cultured-expanded mesenchymal stem cells (ASCs). To avoid high manipulation of the lipoaspirate needed to obtain ASCs and SVF, we investigated whether articular infusions of autologous concentrated adipose tissue are an effective treatment for knee OA patients. METHODS: The knee of 20 OA patients was intra-articularly injected with autologous concentrated adipose tissue, obtained after centrifugation of lipoaspirate. Patients' articular functionality and pain were evaluated by VAS and WOMAC scores at three, six and 18 months from infusion. The osteogenic and chondrogenic ability of ASCs contained in the injected adipose tissue was studied in in vitro primary osteoblast and chondrocyte cell cultures, also plated on 3D-bone scaffold. Knee articular biopsies of patients previously treated with adipose tissue were analyzed. Immunohistochemistry (IHC) and scanning electron microscopy (SEM) were performed to detect cell differentiation and tissue regeneration. RESULTS: The treatment resulted safe, and all patients reported an improvement in terms of pain reduction and increase of function. According to the osteogenic or chondrogenic stimulation, ASCs expressed alkaline phosphatase or aggrecan, respectively. The presence of a layer of newly formed tissue was visualized by IHC staining and SEM. The biopsy of previously treated knee joints showed new tissue formation, starting from the bone side of the osteochondral lesion. CONCLUSIONS: Overall our data indicate that adipose tissue infusion stimulates tissue regeneration and might be considered a safe treatment for knee OA.

Diffusion-weighted imaging for the cellularity assessment and matrix characterization of soft tissue tumour.

PURPOSE: To evaluate whether apparent diffusion coefficient (ADC) of diffusion-weighted imaging (DWI) is able to investigate the histological features of soft tissue tumours. METHODS: We reviewed MRIs of soft tissue tumours performed from 2012 to 2015 to calculate the average ADCs. We included 46 patients (27 male; mean age: 57 years, range 12-85 years) with histologically proven soft tissue tumours (10 benign, 2 intermediate 34 malignant) grouped into eight tumour type classes. An experienced pathologist assigned a semi-quantitative cellularity score (very high, high, medium and low) and tumour grading. The t test, ANOVA and linear regression were used to correlate ADC with clinicopathological data. Approximate receiver operating characteristic curves were created to predict possible uses of ADC to differentiate benign from malignant tumours. RESULTS: There was a significant difference (p < 0.01) in ADCs between these three groups excluding myxoid sarcomas. A significant difference was also evident between the tumour type classes (p < 0.001), grade II and III myxoid lesions (p < 0.05), tumour grading classes (p < 0.001) and cellularity scores classes (p < 0.001), with the lowest ADCs in the very high cellularity. While the linear regression analysis showed a significant relationship between ADC and tumour cellularity (r = 0.590, p ≤ 0.05) and grading (r = 0.437, p ≤ 0.05), no significant relationship was found with age, gender, tumour size and histological subtype. An optimal cut-off ADC value of 1.45 × 10-3 mm2/s with 76.8% accuracy was found to differentiate benign from malignant tumours. CONCLUSIONS: DWI may offer adjunctive information about soft tissue tumours, but its clinical role is still to be defined.

Postmeniscectomy osteonecrosis.

In the last few years, postmeniscectomy osteonecrosis has been reported, especially in elderly patients, with low incidence, unclear physiopathology, and without long periods of follow-up. We report a case diagnosed and followed-up for a 3-year period using magnetic resonance imaging. In the initial phase, a large area of intramedullary edema was evident; after 3 months, the edema had decreased (it was no longer evident at 1 year examination) and a clearly defined area of osteonecrosis was evident with very high signal intensity on high-contrast sequences. After 3 years, the lesion showed a degenerative cyst appearance with an osteosclerotic rim and completely disrupted cartilage.