Primary anaplastic large cell lymphoma of the psoas muscle: a case report and literature review

Soft-Tissue Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma in a Child Unmasked by COVID-19

Anaplastic large cell lymphoma (ALCL) is children's most common mature T-cell neoplasm. The majority is positive for anaplastic lymphoma kinase (ALK). Initial presentation as a soft-tissue pelvic mass without nodal involvement is rare and can be easily misdiagnosed. We report a case of a 12-year-old male presenting with pain and movement restriction in the right extremity. Computed tomography (CT) scan revealed a solitary pelvic mass. Initial biopsy examination concluded rhabdomyosarcoma. After developing pediatric multisystemic inflammatory syndrome due to coronavirus disease 2019 (COVID-19), central and peripheral lymph node enlargement appeared. New cervical adenopathy and pelvic mass biopsies were performed. Immunohistochemistry concluded an ALK-positive ALCL with a small-cell pattern. The patient was treated with brentuximab-based chemotherapy and eventually improved. Differential diagnosis of pelvic masses in children and adolescents must include ALCL. An inflammatory trigger may promote the appearance of a typical nodal disease, previously absent. Attention is warranted during histopathological examination to avoid diagnostic errors.

Extranodal Biphenotypic Non-Hodgkin Lymphoma of the Popliteal Cavity: A Case Report and Review of Literature

Primary soft-tissue lymphoma (PSTL) is a rare extranodal non-Hodgkin lymphoma, characterized by a mass growing within soft-tissue, which is connective tissue, adipose tissue, and skeletal muscle. Here, we describe a case of biphenotypic lymphoblastic lymphoma arising from soft tissue of the popliteal fossa in an 11-year-old boy. A pediatric review about PSTL revealed that anaplastic large cell lymphoma is the most common histological type and a biphenotypic lymphoblastic lymphoma has not yet been reported in childhood. Lymphoma should always be considered in patients presenting with a soft-tissue mass, and a comprehensive immunohistochemical evaluation, including B-cell, T-cell, and myeloid markers, is needed to make a correct diagnosis and establish the most suitable treatment.

ALK-positive anaplastic large cell lymphoma of skeletal muscle masquerading as soft tissue sarcoma

Anaplastic large cell lymphoma (ALCL) is a subtype of T cell non-Hodgkin's lymphoma and can present as an extranodal disease. Primary ALCL of skeletal muscle is rare. We report a case of ALK-positive ALCL involving the left thigh and anterior chest wall in a 12-year-old male child. The fine needle aspiration cytology from the lesion showed cellular smears with singly scattered and occasional clusters of large pleomorphic atypical cells. A diagnosis of poorly differentiated malignant neoplasm was rendered. On core biopsy, the histomorphological features posed a diagnostic challenge with a myriad of morphological mimickers. The diagnosis was established by excluding specific entities by relevant immunostains and confirming the diagnosis by strong expression of CD30 and ALK on immunohistochemistry. Fluorescence in-situ hybridisation confirmed the characteristic t(2:5) translocation. Presentation of ALCL with skeletal muscle involvement is uncommon, and the diagnosis relies on broadening the diagnostic possibilities and judicious use of immunohistochemical markers.

Malignant psoas syndrome associated with gynecological malignancy: Three case reports and a review of the literature

Malignant psoas syndrome (MPS) is a rare and unique cancer-associated syndrome caused by the malignant involvement of the psoas major muscle, and is characterized by ipsilateral lumbosacral plexopathy and painful hip flexion. The pain in MPS is often distressing and intractable, and there is no established effective treatment approach. Herein, the present study reports on three cases of MPS associated with gynecological malignancies, wherein symptom improvement was observed following chemotherapy or radiotherapy. Among 39 cases documented in the literature, female genital tract malignancies were the most frequent causes of MPS; however, the condition may be under-diagnosed, owing to the lack of general recognition. Considering the development of recent high-precision radiation therapy, palliative radiotherapy may serve an important role in the management of MPS. For physicians treating gynecological cancers, early detection of MPS is clinically important as this may allow patients to receive possible therapies and improve their quality of life in end-stage cancer. Further prospective studies should be performed to evaluate effective therapeutic approaches for MPS.

Primary skeletal muscle lymphoma: A case report

Primary lymphomas of the bone or skeletal muscle are rare. Three mechanisms of lymphomatous involvement of the muscle have been described, namely direct invasion from adjacent involved lymph nodes or bone, metastatic spread and, least commonly, primary muscle lymphoma. We herein present a rare case of primary mucle non-Hodgkin lymphoma with a description if the associated clinicopathological findings and a review of the relevant literature. A 41-year-old female patient was referred to our hospital with a painful mass in the right lower extremity. Following resection and histopathological examination, a diffuse large B-cell lymphoma originating from the muscle with cutaneous and subcutanenous infiltration was diagnosed. The patient received chemotherapy with six cycles of cyclophosphamide, hydroxydaunomycin, oncovin and prednisone (CHOP regimen) and a complete radiological response was achieved after six cycles of treatment.

Primary psoas sarcoma causing malignant psoas syndrome: favourable response to radiotherapy

Malignant psoas syndrome (MPS) is an uncommon condition first described by Stevens et al. MPS is caused by malignant infiltration of the psoas muscle and adjacent nerves and is characterised by (fixed) flexion deformity of the ipsilateral hip and proximal lumbosacral plexopathy. It has previously been described in relation to metastatic carcinoma, melanoma and liposarcoma, as well as non-Hodgkins lymphoma. We present the case of a 68-year-old woman with a sarcoma arising in the left psoas muscle at the level of L4 who presented with symptoms of MPS. To the authors' knowledge this is the first case of MPS arising from a primary sarcoma of the iliopsoas compartment. The patient underwent presurgical radiotherapy, with a significant improvement in pain control without an increase in analgesic medications. We discuss the aetiology of MPS and the role of radiotherapy in the treatment of this rare syndrome.

Anaplastic large cell lymphoma with primary involvement of the skeletal muscle: A case report

The present study reported the case of a patient with primary anaplastic large cell lymphoma (ALCL) occurring in the left major psoas. A 24-year-old male patient presented with one-month history of left lower back pain, which had been exacerbated for 10 days prior to admission. Magnetic resonance imaging (MRI) scans revealed an enlarged major psoas muscle that protruded into the inguinal region. The presence of an intense soft tissue mass on MRI scans, as well as the results of fine-needle aspiration biopsy and immunohistochemical analysis of the mass, may help establish an early diagnosis, allowing for the appropriate treatment strategy to be initiated.

Case report: A unique pediatric case of a primary CD8 expressing ALK-1 positive anaplastic large cell lymphoma of skeletal muscle

Primary involvement of skeletal muscle is a very rare event in ALK-1 positive anaplastic large cell lymphoma (ALCL). We describe a case of a 10-year old boy presenting with a three week history of pain and a palpable firm swelling at the dorsal aspect of the left thigh. Histological examination of the lesion revealed a tumoral and diffuse polymorphic infiltration of the muscle by large lymphoid cells. Tumor cells displayed eccentric, lobulated "horse shoe" or "kidney-shape" nuclei. The cells showed immunohistochemical positivity for CD30, ALK-1, CD2, CD3, CD7, CD8, and Perforin. Fluorescence in situ hybridization analysis revealed a characteristic rearrangement of the ALK-1 gene in 2p23 leading to the diagnosis of ALK-1 positive ALCL. Chemotherapy according to the ALCL-99-NHL-BFM protocol was initiated and resulted in a complete remission after two cycles. This case illustrates the unusual presentation of a pediatric ALCL in soft tissue with a good response to chemotherapy.