Primitive myxoid mesenchymal tumor of infancy with brain metastasis: first reported case

Primitive Myxoid Mesenchymal Tumor of Infancy: A Lost Battle

Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a low to intermediate-grade, poorly differentiated myofibroblastic tumor and is characterized by its tendency to recur locally. It commonly occurs in the 1st year of life and is predominantly seen in the axial skeleton and rarely in the retroperitoneum. We report one such case of PMMTI, which is the second case reported in English literature.

Primitive myxoid mesenchymal tumor of infancy, an enigmatic entity: A case report

ABSTRACT

Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a rare soft tissue neoplasm of intermediate malignant potential occurring predominantly in infants and younger children. It can show aggressive local infiltration of surrounding structures and frequent relapses but rare metastasis. Morphologically, it is characterized by a proliferation of immature mesenchymal cells in a myxoid background with mild cytologic atypia and branching vessels. The tumor cells demonstrate immunoreactivity with vimentin and BCOR, however, are negative for more specific lineage markers. Its molecular hallmark is BCOR -internal tandem duplication. Previously classified as infantile fibrosarcoma/undifferentiated sarcoma, the association with BCOR -ITD has led to its reclassification as part of a distinct entity-"Sarcoma with BCOR Genetic Alterations"-in the 2020 WHO Classification of Soft Tissue Tumours. Here is a report of a case of a 2-year-old boy with a recurrent scalp mass identified as a primitive myxoid mesenchymal tumor of infancy.

Treatment of primitive myxoid mesenchymal tumour of infancy: a management paradigm focusing on surgical nuances

Primitive myxoid mesenchymal tumour of infancy (PMMTI) is a rare mesenchymal tumour that typically appears in those under 6 months of age and preferentially affects the deep soft tissues of the trunk and paravertebral spinal regions. PMMTI has only recently been described, and there is scarce literature reporting cases regarding the management paradigm of the tumour. We report the case of an 11-week-old male who presented with bilaterally reduced movement and brisk reflexes in his lower limbs, and irritability. Despite numerous radiological investigations, including MRI, PMMTI was only diagnosed upon biopsy and histopathology. Although PMMTI is known to be relatively unresponsive to chemotherapy, we observed a notable decrease in tumour size after a series of chemotherapy sessions. After two-staged surgical resection of the tumour, the patient is currently stable and under close follow-up. In this article, we aim to report on the patient's clinical presentation, investigations, diagnosis, and treatment, while also discussing the findings from a review of the literature pertaining to future approaches in managing PMMTI. Overall, this case highlights the importance of considering PMMTI in the differential diagnosis of deep soft tissue tumours in young infants and the potential for a combination of chemotherapy and surgical resection to be effective in treating this rare tumour.

Strategies for the Treatment of Infantile Soft Tissue Sarcomas With BCOR Alterations

BCOR alterations are described in ultra-rare infantile soft tissue sarcomas including primitive myxoid mesenchymal tumor of infancy and undifferentiated round cell sarcoma (URCS). Previous reports often describe dismal outcomes. Thus, we undertook a retrospective, multi-institutional study of infants with BCOR -rearranged soft tissue sarcomas. Nine patients aged 6 weeks to 15 months were identified. One tumor carried a BCOR :: CCNB3 fusion, whereas 7 tumors harbored internal tandem duplication of BCOR , including 4 cases classified as primitive myxoid mesenchymal tumor of infancy, 1 case as URCS, and 2 cases characterized by a "hybrid morphology" in our evaluation. Four patients underwent upfront surgery with residual disease that progressed locally after a median of 2.5 months. Locoregional recurrences were observed in hybrid patients, and the URCS case recurred with brain metastases. Complete radiographic responses after chemotherapy were achieved in patients treated with vincristine/doxorubicin/cyclophosphamide alternating with ifosfamide/etoposide, vincristine/doxorubicin/cyclophosphamide alternating with cyclophosphamide/etoposide (regimen I), and ifosfamide/carboplatin/etoposide. Seven patients received radiotherapy. With a median of 23.5 months off therapy, 8 patients are with no evidence of disease. In our study, observation was inadequate for the management of untreated postsurgical residual disease. Tumors demonstrated chemosensitivity with anthracycline-based regimens and ifosfamide/carboplatin/etoposide. Radiotherapy was required to achieve durable response in most patients.

Fine needle aspiration cytology of the primitive myxoid mesenchymal tumor of infancy

Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a recently described entity, previously included under the umbrella of undifferentiated sarcomas. These tumors are notorious for recurrence, chemoresistance and may even metastasize. We describe here, for the first time, the cytomorphology of PMMTI. Further, we discuss the morphological differentials and relevant immunocytochemical markers to reach a correct diagnosis. Knowledge about the distinctive cytomorphological features with characteristic immunocytochemistry is the key to the challenging diagnosis of PMMTI. Establishing the diagnosis on cytology is not difficult in cases of recurrence when such a history is forthcoming. These tumors are a rarity, and awareness of cytomorphology and employment of ancillary techniques is diagnostic, guiding the appropriate therapeutic management.

Case report: Local bleomycin injection: A possible treatment option for primitive myxoid mesenchymal tumor of infancy

In recent years, it has been determined that primitive myxoid mesenchymal tumors of infancy (PMMTI) are solid tumors. To date, very few cases of PMMTI have been reported, and there is no consensus regarding treatment. To provide additional references, it is necessary to collect and report the diagnoses and treatment outcomes of related cases. We report the case of a 38-day-old girl who presented with a 5-cm purple tumor in the right shoulder. Upon hospital admission, the patient received an intratumoral injection of bleomycin after diagnosis of a possible lymphangioma. 10 days after the treatment, the tumor began to develop inflammation and necrosis, resulting in a clear demarcation between the tumor and surrounding tissue. Hence, during the second hospitalization, we performed a successful tumor resection. Postoperatively, the tumor was pathologically diagnosed as PMMTI. 3 months after excision, the patient showed no local recurrence on re-examination. To the best of our knowledge, this is the first report of a PMMTI in which bleomycin, or other similar chemotherapeutic drugs, have been injected into tumors. This result offers novel insights into the treatment of PMMTI. Injection therapy with bleomycin and similar chemotherapeutics may result in specific responses to PMMTI, which may help in developing better surgical conditions or improving outcomes in non-surgical patients.

Primitive Myxoid Mesenchymal Tumour of Nose

Primitive Myxoid Mesenchymal Tumour of Infancy (P.M.M.T.I.) is a locally aggressive myofibroblastic tumour, occurring mostly in the first year of life. Grossly, it occurs as a non-encapsulated, multi-nodular tumour with focal infiltrative growth with a size ranging from 2 to 15 cm. It is composed of primitive spindled cells in a myxoid background. It is a low-grade fibroblastic malignancy with low metastatic potential with a high local recurrence rate. On immunohistochemistry, it stains positive for Vimentin. no reactivity for smooth muscle actin, muscle specific actin, desmin, S-100 protein, or myogenin. Electron microscopy documented a poorly differentiated fibroblastic proliferation. The present case is of a P.M.M.T. occurring in the nose of a 3 ½ years old female child. This is the first case reported from Central India. The child had recurrent nasal growth and the excision biopsy was suggestive of intermediate grade fibroblastic neoplasm. The biopsy, on IHC staining, was positive for Vimentin and CD99 and negative for S-100, CD-34 and Desmin, favouring the diagnosis of P.M.M.T. The child had a total of three recurrence of growth after local excision before diagnosis was established. In the prior two surgeries, the histopathological analysis reported it as a benign nasal polyp. After the third surgery, the specimen was sent for IHC. Immunohistochemical stains helped in differentiating it from congenital infantile fibrosarcomas, a similar type of mesodermal tumour. The present case of Primitive myxoid mesenchymal tumour following IHC stains were positive for Vimentin, CD-99, CD-117 and NESTIN, pointing to the primitive nature of the tumour. It was negative for the neural marker. Since it is chemo resistant, the preferred method of treatment is wide surgical excision.

Primitive Myxoid Mesenchymal Tumor of Infancy in the Orbit: A New Location for a Rare Tumor

Primitive myxoid mesenchymal tumor of infancy is a rare subtype of sarcoma. With the advent of relevant immunohistochemical and genetic analysis, it was defined by Alaggio et al. in a 2006 case series. Since then, 25 further cases are described in the literature-arising variably from the neck, chest, scalp, abdomen, back, or limbs. Here it is described for the first time arising in the orbit, confirmed by identification of BCOR immunopositivity with internal tandem duplication. All specialties involved in the management of orbital masses should be aware of the subtypes of sarcomas found in the orbit as approaches to their management may change depending on the diagnosis. As more cases are identified, a better understanding of this tumor's clinical behavior and appropriate management can be established.

Pediatric thoracic mass lesions: Beyond the common

Thoracic mass lesions can be categorized as originating in one of the three major compartments: a) chest wall and pleura, b) lung parenchyma and airways, c) mediastinum. While some of these, such as lymphoma, are common in both children and adults, others are rare and unique to childhood. The goal of this review is to familiarize radiologists with unusual but distinctive mass lesions of the pediatric thorax.

Management of Unresectable Metastatic Primitive Myxoid Mesenchymal Tumor of Infancy: A Case Report and Systematic Review of the Literature

Primitive myxoid mesenchymal tumor of infancy is a rare soft tissue tumor. The present case is one of the most invasive primitive myxoid mesenchymal tumor of infancy reported to date. To our knowledge, it is the first case described with extensive involvement of pelvis and the third described developing metastasis and with an invasion of the spinal canal without evidence of transformation into undifferentiated sarcoma. The patient failed to respond to chemotherapy (CHT). According to the few available data, CHT seems to be more effective in the presence of metastatic disease or increased cellularity. However, CHT, including high-dose ifosfamide, resulted ineffective even after lung metastasis development with pathologic evidence of increased mitotic rate. The management of this case and the data in the literature confirm surgery as the gold standard treatment in this pathology.