Temporal hemiarthroplasty for distal femoral osteosarcoma in early childhood: a case report.

BACKGROUND: Prosthetic reconstruction for distal femoral osteosarcoma is challenging for younger children. We herein report a successful case of limb-sparing surgery for a younger patient with distal femoral osteosarcoma requiring osteo-articular resection. CASE PRESENTATION: A 5-year-old girl with high-grade conventional osteosarcoma in the left distal femur underwent a series of surgeries. After three cycles of neoadjuvant chemotherapy, limb-salvage surgery was planned because femoral rotationplasty had been refused. At 6 years and 2 months old, distal femoral resection and temporary spacer insertion using a 7-mm-diameter intramedullary nail and molded polymethylmethacrylate was performed. At 7 years and 8 months old, secondary surgery was performed because the first spacer had been dislocated and the residual femur became atrophic. The distal end of the residual femur was removed by 1 cm, but the periosteum and induced membrane around polymethylmethacrylate was preserved. In order to stabilize the spacer against the tibia, a custom-made ceramic spacer with a smooth straight 8-mm-diameter stem was utilized. The bone-spacer junction was fixed with polymethylmethacrylate and then covered with the preserved periosteum and induced membrane. After surgery, the bone atrophy improved. At 9 years and 7 months old, the second spacer was removed because it had loosened, and the knee joint was reconstructed using a custom-made growing femoral prosthesis with a curved porous 8.5-mm-diameter stem. Cancellous bone tips from the proximal tibia were grafted around the bone-prosthesis junction underneath the induced membrane. At 10 years and 5 months old, the patient was able to walk unsupported and a radiograph showed further thickening of the cortex of the residual femur without any stress shielding. Although having 5 cm of limb length discrepancy, the patient and her mother were satisfied with the function. The MSTS score was 24 out of 30 points. Repeated limb length extensions are planned. CONCLUSIONS: This case report provides an example of limb-salvage surgery after distal femoral resection in a small child. The use of a temporary spacer utilizing partial cementation and preservation of the periosteum and induced membrane appears to afford a viable limb-salvage option after distal femoral resection for younger children.

Acute Myocardial Infarction in an Adolescent Receiving Anagrelide for Essential Thrombocythemia with Underlying Persistent Coronary Endothelial Dysfunction.

Essential thrombocythemia (ET) is a Philadelphia chromosome-negative myeloproliferative disorder that is characterized by the overproduction of platelets and a marked increase in the numbers of mature megakaryocytes present in the bone marrow. Thrombohemorrhagic disorders are major morbidities of ET, especially those with mutations in the gene encoding Janus kinase 2 (JAK2). In this study, we report the case of an 18-year-old patient with ET carrying JAK2 mutation who developed acute ST-elevation myocardial infarction (STEMI) 5 months after a commencement of anagrelide. Coronary endothelial dysfunction confirmed by positive acetylcholine provocation test lasted a year after the occurrence of STEMI. Furthermore, intracoronary imaging using optical coherence tomography demonstrated non-atheromatous intimal fibrosis possibly due to chronic endothelial damage. The coronary pathologies reflected chronic change potentially associated with properties of ET and JAK2 mutation in addition to hyperviscosity. These observations suggest that the side effect of anagrelide in our patient was considered causative, while underlying chronic endothelial dysfunction and adverse endothelial remodeling may be predisposing factors to his fatal cardiovascular events.

[Pathological Findings of Chronic Effects Observed in the Kidneys Exposed to Antineoplastic Agents in Two Adolescent Patients].

Cisplatin and ifosfamide are well-known nephrotoxic agents that can cause acute and chronic glomerular and/or tubular toxicity. We examined 2 adolescent patients who were receiving cisplatin and ifosfamide treatments. Pathological findings of patient 1 showed acute tubular necrosis-like patchy injury. Tubulointerstitial nephrosis and glomerular sclerosing were revealed in patient 2. These findings were consistent with the known damages induced by cisplatin and ifosfamide. Proteinuria and mild decline of eGFR were noticed after more than 10 months after the completion of the treatment. It is important to monitor such consequences in long-term follow up. Adult based medical services are required for childhood and adolescent cancer survivors.

Rare Case of BCOR::CCNB3 Sarcoma of Bone.

BACKGROUND BCOR: CCNB3 sarcoma is a rare mesenchymal tumor that was formerly included in the undifferentiated/unclassified sarcoma group and was recently reclassified as one of undifferentiated small round cell sarcomas with a genetically distinct subtype in the WHO 2020 classification. Because of its rarity, still not much is known, especially about its clinical features. CASE REPORT A 15-year-old boy presented with almost 1-year intermittent thigh pain. On the first visit, a pathologic fracture of the femur and a big mass expanding through the femoral cortex with lobular shape and homogenous appearance were recognized on radiography and magnetic resonance imaging. Plain radiography, which was taken 6 months before at a local clinic, showed an expansion and thickening of the right proximal femoral shaft. Biopsy specimen of the lesion revealed a proliferation of round to spindle tumor cells with diffuse and strong immunohistochemical nuclear positivity for BCOR and CCNB3. Under the diagnosis of BCOR::CCNB3 sarcoma of the femur, a chemotherapy based on a protocol of Ewing sarcoma, followed by a wide resection and total femoral replacement surgery, were conducted. The effect of chemotherapy was favorable, showing no microscopic residual tumor. Although postoperative chemotherapy was not completed because of a minor infection detected on the surgical site, the patient was doing well, without any recurrence, for 26 months. CONCLUSIONS BCOR: CCNB3 sarcoma of the bone is a quite rare tumor with much lower incidence than Ewing sarcoma. Notable clinical characteristics of the current case were a 1-year-long symptomatic period and homogenous appearance on MRI.

Lethal macrophage-related complications of juvenile myelomonocytic leukemia with a blastic crisis: an autopsy case report.

For hematopoietic stem cell transplantation to be successful, complications must be managed. Graft-versus-host disease is particularly important, but various other complications, treatment side effects, and relapse of primary disease may also occur. We report an autopsy case of juvenile myelomonocytic leukemia with a blastic crisis, in which activated and recovered autologous macrophage-related complications after cord blood transplantation caused the patient's death. Pathological analysis of autopsy specimens revealed diffuse infiltration of mature macrophages into the skin but scarce lymphocytes. These macrophages were found in the bone marrow interspersed with a small number of blasts that had previously occupied about 60% of the bone marrow before death. The direct cause of death was an opportunistic airway infection due to bone marrow and immune failures triggered by overactivation and proliferation of macrophages. Genetic analysis showed the activated macrophages were autologous. Together these findings indicate that the patient died from macrophage-mediated complications, but not from a blastic crisis or conventional graft-versus-host disease. When macrophage activation persists after hematopoietic stem cell transplantation, macrophage-mediated complications should be considered as a differential diagnosis. To manage this complication, pathology specimens should be examined to check for the presence of effector cells at an early stage.