BACKGROUND: Solitary fibrous tumor (SFT) is a remarkably uncommon mesenchymal tumor. STAT6 level and a combination of clinical, pathological, and molecular features are required to arrive at a proper diagnosis.
METHODS: In this report, we present an intriguing case involving a 43-year-old woman who initially exhibited symptoms of a bleeding retroperitoneal tumor, initially resembling a gastrointestinal stromal tumor, but later confirmed as an SFT. However, a year later, what was initially believed to be a recurrence of her SFT was instead identified as a desmoid tumor.
CONCLUSIONS: Distinguishing SFT from other tumors was pivotal. Correcting misdiagnoses of tumor type initially and of recurrence later was necessary for appropriate treatment of the correct desmoid type.

METHODS: This case report describes a patient who presented with clinical and radiographic features of a soft tissue sarcoma of the shoulder. Despite having a painless and relatively large mass, a biopsy and resection revealed nodular fasciitis (NF).
CONCLUSIONS: This is an unusual case of a painless 10 cm mass that histopathologically was diagnosed as NF in the upper extremity with proximity to the axillary nerve and posterior humeral circumflex vessels. The USP6 rearrangement was helpful in confirming the diagnosis. Careful clinical, radiographic, and pathologic correlation is necessary in diagnosing these relatively rare tumors. In cases where there are discordant findings, molecular markers can be very helpful.

Tenosynovial giant cell tumor (TGCT) is a rare type of neoplasm that may be locally aggressive but is most often benign and can be divided into two subtypes: localized and diffuse. It tends to develop in the joints, bursae, and tendon sheaths primarily in the digits of the hand and less commonly in the forefoot. This soft-tissue mass has many possible differential diagnoses, including lipoma, ganglion cyst, plantar fibroma, and various sarcomas; surgical excision is usually indicated to reach a definitive diagnosis and rule out malignancy. We report a rare case of a 30-year-old woman with atypical plantar hallucal pain and a palpable mass on the plantar lateral aspect of the left hallux. Surgical excision and histopathologic evaluation confirmed a TGCT of the left hallucal flexor tendon sheath. Although it bears clinical resemblance to several other soft-tissue masses, TGCT has numerous pathognomonic features evident with advanced imaging and histologic analysis that help the physician obtain an accurate diagnosis and proceed with appropriate treatment.

Soft-tissue sarcomas (STS) are rare solid tumors of mesenchymal cell origin and account for only 1% of adult malignancies. They tend to occur most commonly in the lower extremities. Reconstruction after sarcoma resection can be challenging, especially when important structures are involved and recurrences occur. Additionally, more attention is now being paid to reconstructing the lymphatic system to prevent lymphatic complications. In this case report, we presented the management of recurrent medial thigh sarcoma that necessitated multiple challenging reconstructions to provide valuable insights for lectures on similar cases. A 50-year-old male patient was diagnosed with an undifferentiated pleomorphic cell sarcoma (UPS) of the anteromedial thigh. After preoperative radiotherapy, a mass of 23 × 15 cm was removed, and reconstruction with a pedicled deep inferior epigastric artery perforator (p-DIEP) flap-based lymphatic flow through (LyFT) was performed. Six months later, the patient developed the first local recurrence with the presence of a distant metastasis. Following the tumor resection, the medial part of the DIEP flap was de-epithelized and buried in the defect for dead space obliteration. Another local recurrence arose 7 months after the second surgery. Therefore, a major debulking surgery involving the femoral neurovascular bundle was performed. The femoral artery was reconstructed with a synthetic graft, and the femoral vein with the great saphenous vein harvested from the contralateral thigh. A composite myocutaneous neurotized anterolateral thigh (ALT) flap from the contralateral thigh was used to obliterate the defect and restore the loss of function of the quadriceps femoris. Two lymphaticovenular anastomoses (LVAs) were performed at the ankle to reduce the risk of lymphatic sequelae. This case report highlights the importance of integrating various techniques to create a tailored approach that effectively addresses complex surgical requirements to avoid limb amputation and maintain functionality.

BACKGROUND: Myxofibrosarcoma is a myxoid soft tissue sarcoma showing T2 high intensity on magnetic resonance imaging. However, myxofibrosarcoma is a heterogeneous sarcoma with both myxoid and cellular portions. Magnetic resonance imaging findings were obtained MRI findings for comparison with histological and Ki-67 immunohistochemical features, in different portions of one myxofibrosarcoma.
METHODS: Magnetic resonance imaging observations were compared with gross pathological and microscopic findings of a myxofibrosarcoma from a 50-year-old Japanese female. The Ki-67 labeling indices of different portions of the tumor, that is, the myxoid, cellular, and histologically confirmed infiltrative margin portions (pathological tail sign), were compared. The T2 low intensity area was more cellular than the T2 high intensity area, while the cellular portion had a significantly higher Ki-67 index than the myxoid portion (p = 0.0313). The portions with the pathological tail sign had a significantly higher Ki-67 labeling index than those without this sign (p = 0.0313).
CONCLUSIONS: More cellular portions of a myxofibrosarcoma correspond to more areas of the tumor showing aggressive features. Furthermore, our data also support the hypothesis of high aggressiveness being associated with the pathological tail sign in myxofibrosarcoma. To our knowledge, this is the first case report to describe comparisons among the imaging findings, histological features, and Ki-67 immunohistochemistry results for different portions of one myxofibrosarcoma.

UNASSIGNED: Among liposarcomas, well-differentiated liposarcoma and dedifferentiated liposarcoma are the most common. The majority of these tumors are found in deep retroperitoneum or extremities. When found outside the retroperitoneum, these adipose-derived tumors are known as atypical lipomatous tumors (ALT). Superficial ALT are particularly rare; thus, little is known about their clinical presentation, genomic status, and management. Here, we present the case of a 54-year-old man with an intermittently bothersome, slowly growing mass on his left upper back for over 2 years, which was incidentally diagnosed as ALT. This patient\'s ALT, however, showed a profound degree of pleomorphism with MDM2 and control centromere 12 (CEP12) coamplification and negative CD34 and S100 and RB1 expression, unlike most other ALT described in the literature. This case report details the diagnostic workup and histopathological findings for adipose tumors and summarizes the different subtypes, including atypical spindle cell/pleomorphic lipomatous tumor, pleomorphic liposarcoma, and spindle cell/pleomorphic lipoma, with brief discussion on management.

Dedifferentiated liposarcoma (DDLPS) is a non-lipogenic sarcoma, generally arising from well-differentiated liposarcoma (WDLPS), although it can develop de novo. DDLPS tumors rarely trans-differentiate into non-adipose mesenchymal tissues; however, the latter lack notable variety and mostly show striated muscle or osteogenic/chondrogenic differentiation. Here, we report a case of DDLPS that contained numerous atypical vessels. A man in his sixties presented with a large tumor in his right thigh, and the tumor was surgically resected. Microscopically, most of the tumor was WDLPS, but a minor portion showed DDLPS, consisting of high-grade spindle cells. Remarkably, the DDLPS contained vessels of various sizes with atypical cytoarchitecture, including vessels with seemingly muscular layers. Immunohistochemically, the atypical cells within the vascular wall expressed aSMA, consistent with smooth muscle cells or pericytes, whereas surrounding high-grade spindle cells only focally expressed it, and these aSMA-positive cells within the vessels exhibited MDM2 amplification by immuno-fluorescence in situ hybridization. Our results demonstrate that DDLPS can trans-differentiate into smooth muscle cells of various-sized accompanying vessels, which may support their survival and proliferation.

Ectomesenchymal chondromyxoid tumor (ECT) is a rare soft tissue tumor with peculiar histogenesis, exhibiting a predilection for the dorsum of the tongue. Molecular evidence suggests that it may originate from the migration of ectomesenchymal pluripotent cells from the neural crest to the tongue, where these cells may eventually proliferate and undergo myxoid and chondroid differentiation. This article illustrates a case of a 16-year-old female patient who presented with a nodule on the dorsum of her tongue, which had been present for four years. Surgical excision was performed, and histopathological analysis revealed a myxoid neoplasia composed of polygonal and spindle cells within a loose stroma containing chondroid areas. Tumor cells were positive for GFAP and S-100 proteins on immunohistochemical study, confirming the diagnosis of ECT. After a 5-year follow-up, the patient has shown no evidence of recurrence. Although rare, ECT can be diagnosed straightforwardly due to its distinctive clinical, histopathological, and immunohistochemical features. Clinicians and pathologists should become familiar with this tumor in order to avoid misdiagnosis.

BACKGROUND: Angioleiomyoma is a benign soft-tissue tumor that arises from the smooth muscle cells in the tunica media of the blood vessels. Although the most common location for these neoplasms is the uterine wall, they can also originate from lower limbs. Altogether, these neoplasms account for 0.2% of all those located in the foot and ankle region. Signs and symptoms of foot angioleiomyoma can be a localized pain, swelling, and functional impairment. To date, only case reports and case series with small populations have been reported in the literature to describe the clinical picture of these neoplasms and the effectiveness of surgical treatment. In this study, we report our results of surgical treatment for angioleiomyomas of the foot.
METHODS: Thirteen cases suffering from angioleiomyoma of the foot underwent surgical resection in our institution between January of 2017 and January of 2022. For each case, we recorded preoperative and postoperative symptoms, and their preoperative and postoperative functional status according to both Musculoskeletal Tumor Society Score (MSTS) and American Orthopedic Foot and Ankle Society Score (AOFAS). Eventual complications and local recurrence were reported.
RESULTS: Each patient had at least mild pain before surgical treatment. The mean preoperative MSTS and AOFAS were 22.1 and 76.8, respectively. The mean tumor size was 17.7mm. Preoperatively, each patient underwent resection with wide margins. None had local recurrences or major complications at their latest follow-up. After surgery, the mean postoperative MSTS and AOFAS increased to 29.5 and 98.8, respectively. Each case had a marked increment of their functionality and a reduction of their pain after surgery.
CONCLUSIONS: Our results suggest that surgical approach with tumor resection should be considered a safe and reliable treatment for foot angioleiomyomas in light of the extremely low risk of local recurrence and because of the good postoperative pain relief and functional restoration that can be obtained after the treatment.

BACKGROUND: Synovial hemangiomas are rare benign vascular anomalies surrounded by a synovial lining and were first described by Bouchut in 1856. These neoplasms can develop in the intra-articular region, resulting in effusions and knee pain. However, their cause remains unknown. Prompt diagnosis and intervention are critical to prevent chondral damage. Histopathological examination is used to achieve the diagnosis, which is often delayed because of a lack of specific clinical signs. This report describes a unique case in which a painful infrapatellar mass was diagnosed as a synovial hemangioma. The absence of typical magnetic resonance imaging (MRI) findings highlights the importance of arthroscopic excision for diagnosis and symptom relief.
METHODS: A 20-year-old woman presented with persistent anterior left knee pain that became exacerbated when she climbed stairs. Despite previous pain management and physical therapy, she developed a painful lump beneath her patella that worsened over time. She had also undergone arthrocentesis, but this did not relieve her pain. Physical examination revealed a palpable, immobile 5-cm mass along the patellar tendon with limited knee flexion and extension and normal ligament stability. T1-weighted fat-saturated MRI of the left knee with gadolinium-based contrast revealed a lobulated intra-articular mass in Hoffa\'s fat pad that resembled a soft tissue chondroma. A biopsy of the mass was performed to provide histopathological evidence, confirming the benign nature of the mass. The subsequent excisional arthroscopy, combined with incision enlargement for mass removal, confirmed the histopathologic diagnosis of synovial hemangioma based on the presence of numerous dilated blood vessels and venous proliferation within sections of the synovium. Recovery was complete, and no residual tumor was detected on follow-up MRI after 1 year.
CONCLUSIONS: This case study emphasizes the importance of arthroscopic excision over open surgery for patients with synovial hemangioma. The minimally invasive nature of arthroscopy combined with the well-encapsulated nature and location of the mass facilitates complete resection.