Leiomyomas and schwannomas are both types of rare benign soft tissue tumours. Leiomyomas are more commonly found in the lower limbs than in the upper extremities, while schwannomas are rare peripheral nerve sheath tumours that can occur in different anatomical regions. However, they rarely occur in the saphenous nerve. This case study presents a 41-year-old female patient with a solitary mass lesion located deep in the soft tissue of the anteromedial lower extremity. The physical examination revealed a palpable, elastic-hard, mobile and non-tender mass. Magnetic resonance imaging (MRI) showed an oval-shaped subcutaneous mass on contrast-enhanced T1-weighted sections. The initial MRI images suggested a schwannoma, but the tumour was later confirmed to be a leiomyoma after total enucleation. An immunohistochemical study was performed for differential diagnosis. Solitary mass lesions in the lower extremities can be mistaken for various types of tumours and misdiagnosed and require histopathological examination and good radiological imaging for differential diagnosis. Complete surgical excision is usually a safe and effective treatment for leiomyomas.

Juxta-articular myxoma (JAM) is a rare soft tissue tumour predominantly composed of mucinous tissue and usually found around large joints. We report a 73-year-old woman with a 5-year history of a soft tissue mass in the thenar eminence of the right wrist who presented to our department. An initial diagnosis of a ganglion cyst was made using magnetic resonance imaging (MRI) and the jellied content of the mass by aspiration. Two years after presentation, surgical treatment with tumour resection and carpal tunnel release via the radial approach was performed because the symptoms of carpal tunnel syndrome worsened, and the tumour invaded the carpal tunnel. Histopathological examination revealed a JAM. At the 1-year follow-up, the symptoms of carpal tunnel syndrome had resolved, and no recurrence was confirmed by MRI. Level of Evidence: Level V (Therapeutic).

Solitary fibrous tumour (SFT) is a mesenchymal neoplasm with variable behaviour, very rarely involving the genitourinary (GU) tract. Most reported cases correspond to isolated case reports. STAT6 immunohistochemistry is a more recent and reliable diagnostic marker. The pathology database of two tertiary institutes was searched for SFTs involving the GU tract. STAT6 strong diffuse nuclear staining confirmed the diagnosis in all four cases, and the NAB2::STAT6 fusion was demonstrated by NGS in one case. Two cases were diagnosed in needle biopsy, one involving the prostate and the other involving the seminal vesicle. One case corresponded to a pelvic mass inseparable from and infiltrating the prostate and bladder. The remainder represented an exceedingly rare involvement of the spermatic cord. Involvement by a SFT should be considered in the differential diagnosis of spindle cell lesions involving GU organs. STAT6 strong diffuse nuclear staining is an important ancillary tool, particularly in a biopsy.

Myxofibrosarcoma (MFS) is a soft tissue sarcoma that commonly occurs in late adult life. It is mainly located in the subcutaneous soft tissues of extremities characterized by a high recurrence rate at the original site. MFS of the head and neck is rare, while it occurrence in the maxilla is extremely rare. We report an atypical case of MFS of the maxilla in a 29-year-old male. The tumour was resected with adequate margin and following which post-operative adjuvant radiotherapy was given. This patient has been followed for 2 years to date and has remained disease free. The rarity, the aggressive nature of the pathology, the extent of the tumour and the complex neurovascular structures in close proximity to the site often lead to adverse outcomes. We will be discussing a rare case of a rapidly growing high grade maxillary sinus MFS in a young patient with a history of radiation exposure which posed as a diagnostic challenge. Our case may provide additional diagnostic and treatment experience with regards to managing maxillary sinus myxofibrosarcoma.

Low-grade fibromyxoid sarcoma (LGFMS) is a soft tissue neoplasm that occurs preferentially in young, male adults as a slowly growing, asymptomatic mass. According to current literature, the most common anatomical sites where it occurs are the trunk and lower extremities, especially the thigh, perineum, and groin. The risk factors are still unknown. Surgical intervention (simple resection and wide excision) is nowadays considered the best treatment option; however, patients require a long follow-up due to the high recurrence and metastasis rates. We present a low-grade fibromyxoid sarcoma case located in the abdominal wall of a female Hispanic patient.

Osteomas are benign, slow-growing, differentiated tumours, which are primarily located in the region of maxillofacial skeleton. Osteoma involving the soft tissues with no bony attachments is a very rare event. A 68-year-old woman with comorbidities (diabetes mellitus type II, primary hypertension, pacemaker in situ) presented with a painless solid mass in the thenar region of her right palm, which appeared almost 1 and half years ago and showed a progressive enlargement in the last few months. Under regional anaesthesia, an excisional biopsy was performed and the histopathological evaluation of the lesion confirmed the diagnosis of soft tissue osteoma. The postoperative follow-up period was uneventful without any complication.

BACKGROUND: Fibrous hamartoma of infancy is a rare soft tissue tumour that usually appears before 2 years of age, typically in the upper extremities of male infants.
METHODS: We report the case of a 2 year old boy with a large and rapidly growing tumour in the upper extremity.
CONCLUSIONS: We describe the case, its differential diagnosis and the immunhistological characteristics, and we discuss the non-aggressive surgical treatment, based on the benign behaviour of this tumour.
BACKGROUND: El hamartoma fibroso de la infancia es un raro tumor de partes blandas, que aparece antes de los 2 años de edad, típicamente en varones, en las extremidades superiores.
METHODS: Presentamos el caso de un niño de 2 años con una gran masa de crecimiento rápido en miembro superior.
UNASSIGNED: Se realiza descripción del caso, del diagnóstico diferencial y de sus características inmunohistológicas y se discute el tratamiento quirúrgico no agresivo, basado en el comportamiento benigno del tumor.

Fibrous histiocytoma is a benign soft tissue tumour that may present as a fibrous mass anywhere in the human body. The involvement of the oral cavity is extremely rare and very few cases have been reported in literature till date. We here report a case of benign fibrous histiocytoma localized in the oral cavity. The clinical and histological features of the lesion are discussed precisely in the light of a literature review of this pathology in oral cavity.

Low-grade fibromyxoid sarcoma (LGFMS) are rare soft-tissue sarcomas that usually come to attention as slow growing masses. Males and females are affected approximately equally and typically arising in the soft tissue of the proximal extremities. Primary occurrence within the head and neck is exceedingly rare. We report a case arising from the hard palate of a 40-year-old male and according to our knowledge this is the first ever case of LGFMS involving the palate to be reported.

We report a case of a 43-year-old female, presented with complaints of breathlessness for 1 month and had three episodes of syncopal attacks in the past two months. On clinical evaluation, bilateral pedal oedema was noticed. Echo cardiogram revealed large left atrial blood clot measuring 5.7x4.3x4.3 cm. Ultrasound whole abdomen was normal. We received an excised mass with right pulmonary vein end arterectomy speciemen. Histopathology of the mass revealed characteristic features of leiomyosarcoma with grade III, according to FNCCS grading system. The tumour was consistent with substantial amount of poorly differentiated fasicles of pleomorphic spindle cells and brisk atypical mitosis, with marked necrosis. Immunohistochemistry revealed the tumour cells in strong diffuse cytoplasmic positive for smooth muscle actin and Ki-67 showed 15-20% of tumour cells postivity. The prognosis depends on the individual tumour origin for individual site, size of tumour and depth of tumour than histological features. Pulmonary venous leiomyosarcomas were assumed to be misinterpretation of left atrial leiomyosarcomas with growth of the tumour into pulmonary vein lumen. We report this case in view of its extreme rarity.