Myofibroma, Myopericytoma, Myoepithelioma, and Myofibroblastoma of Skin and Soft Tissue

Parotid Mass in an 81-Year-Old Woman

An 81-year-old woman presented with a 3-month history of a slow-growing mass in her left cheek and denied having any symptoms, tenderness, numbness, or facial nerve weakness. What is your diagnosis?

Uncommon and peculiar soft tissue sarcomas: Multidisciplinary review and practical recommendations. Spanish Group for Sarcoma research (GEIS -GROUP). Part II

Among all Soft Tissue sarcomas there are some subtypes with low incidence and/or peculiar clinical behaviour, that need to be consider separately. Most of them are orphan diseases, whose biological characteristics imply a clearly different diagnostic and therapeutic approach from other more common sarcoma tumors. We present a brief and updated multidiciplinary review, focused on practical issues, aimed at helping clinicians in decision making. In this second part we review these subtypes: Alveolar Soft Part Sarcoma, Epithelioid Sarcoma, Clear Cell Sarcoma, Desmoplastic Small Round Cell Tumor, Rhabdoid Tumor, Phyllodes Tumor, Tenosynovial Giant Cell Tumors, Myoepithelial Tumor, Perivascular Epithelioid Cell Neoplasms (PEComas), Extraskeletal Myxoid Chondrosarcoma, NTRK-fusions Sarcomas. Most of them present their own radiological and histopathological feautures, that are essential to know in order to achieve early diagnosis. In some of them, molecular diagnosis is mandatory, not only in the diagnosis, but also to plan the treatment. On the other hand, and despite the low incidence, a great scientific research effort has been made to achieve new treatment opportunities for these patients even with approved indications. These include new treatments with targeted therapies and immunotherapy, which today represent possible therapeutic options. It is especially important to be attentive to new and potential avenues of research, and to promote the conduct of specific clinical trials for rare sarcomas.

Myofibromatosis

INTRODUCTION

Myofibromatosis is a distinctive mesenchymal disorder occurring predominantly in childhood, which on microscopy shows peripheral light areas of spindle cells and central cellular areas of primitive oval to spindle cells arranged around hemagiopercytomatous vessels. PDFGRB mutations in the familial and multifocal sporadic forms and SRF-RELA fusions in the cellular variants have been identified. The index case is being presented to discuss the clinico-pathological features, differential diagnosis, and management of the lesion.

CASE PRESENTATION

An 11-year-old male presented with an infraorbital mass of 3 months duration. The mass was excised and microscopy revealed the morphological features of myofibroma with tram-track SMA immunopositivity. Nodular fasciitis and fibromatosis were the differentials considered.

CONCLUSION

The SRF-RELA gene fusion may represent a subset that in the future may be used to differentiate these myofibromas/myopericytomas from the ACTB-GLI fusion myopericytomas, and PDGFRB may be used to perhaps separate out familial myofibromas from other myofibromas.

Nonepithelial Tumors and Tumor-like Lesions of the Skin and Subcutis in Children

This overview of mesenchymal tumors presenting in the skin and/or subcutis in children brings together the range of neoplasms and hamartomas which are seen in this age-group. It is not surprising from the perspective of the pediatric or general surgical pathologist that vascular anomalies, including true neoplasms and vascular malformations, are the common phenotypic category. Since there is considerable morphologic overlap among these lesions, clinicopathologic correlation may be more important than for many of the other mesenchymal tumors. The skin and subcutis are the most common sites of clinical presentation for the infantile myofibroma which is the most common of fibrous mesenchymal tumors in children. Several of the other mesenchymal tumors are more common adults-like dermatofibrosarcoma protuberans, but nonetheless have an important presence in children, even as a congenital neoplasm. A lipomatous tumor in a young child should be considered as a possible manifestation of an overgrowth syndrome.

Putative Intravascular Myofibroma Mimicking a Vascular Malformation With Phleboliths

Myofibroma is a rare, benign myofibroblastic tumor that commonly presents at birth or in early infancy, usually as a painless, slow-growing, solitary, nodular mass. We present a case of a 40-year-old woman with a painful, solitary, myofibroma on the right elbow. The unique features of this case include age and gender of the patient, site, pain on presentation, tumor morphology, and putative intravascular nature of the tumor.

Myofibroblastoma of the mandible in a 3-year-old child

Myofibroblastoma is a rare benign tumor of the head and neck region, which is characterized by a large, rapidly growing, and destructive mass. A 3-year-old boy presented with an 8-week history of a rapidly growing swelling of the right mandible. Examination revealed a firm 13-cm mass occupying the entire right body and ramus of the mandible. The clinical and radiological features were suggestive of a sarcoma. An initial biopsy taken in the referring hospital was inconclusive, and the second biopsy showed a myofibroblastic neoplasm consistent with a desmoplastic fibroma. Progressive tumor growth necessitated a tracheostomy. Right hemimandibulectomy was performed, and the defect was reconstructed with free microvascular fibula flap. Histopathology and immunocytochemistry revealed a myofibroblastoma. This entity differs from other myofibroblasts and fibroblast tumors such as inflammatory myofibroblastic tumor (IMT), myofibroma, and desmoplastic fibroma. The child has been followed up for 2 years.

CONCLUSION

Differentiation between myofibroblasts and fibroblastic tumors as well as some malignancies can be challenging. Myofibroblastoma can behave as a malignant neoplasm, and the clinical distinction of this entity lies primarily in its recognition as a benign neoplasm.