The Spectrum of Pediatric Fibroblastic and Myofibroblastic Tumors

Congenital Myofibroblastic Skin Tumours in a Newborn Piglet Resembling the Multicentric Form of Infantile Myofibromatosis

A 2-day-old female piglet was submitted with multiple congenital, nodular skin masses located on the head, neck, trunk and legs. Histopathological examination revealed the presence of nodular, cutaneous tumours with a biphasic growth pattern and comprising a population of undifferentiated, oval or slightly polygonal, frequently perivascularly located cells and a population of spindle-shaped, fibroblast-like cells arranged in bundles. Multifocally, tumour cells infiltrated subcutaneous adipose and muscular tissue. Immunohistochemically, the undifferentiated tumour cells expressed vimentin and calponin, whereas the spindle-shaped tumour cells were positive for vimentin, α-smooth muscle actin and calponin. Based on these findings, the diagnosis was myofibroblastic tumours closely resembling the multicentric form of human infantile myofibromatosis.

New insights on fibrodysplasia ossificans progressiva: discussion of an autoptic case report and brief literature review

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic condition with soft tissue progressive ossification, leading to severe disability. We describe a 27-years-old female affected by FOP who died after a fall. An autopsy was performed. Upper and lower extremities resulted in fixed flexion, with kyphoscoliosis of the spine and chest wall deformity. Moreover, a cranial fracture was pointed out. At histology, atypical abundance of corpora amylacea in gray matter was observed. In a sample of macroscopically non-affected muscular tissue, small areas with necrosis of myocytes and hyperplasia of fibroblasts were seen in light microscopy, with intracellular inorganic dystrophic inclusions in transmission electron microscopy. Thyroid gland histology showed diffuse lymphocytic infiltration. Postmortem examination of FOP patients provided precious information about involvement of other tissues, suggesting an initial and widespread inflammatory/dystrophic phase, to be further investigated, because it might reveal new insights about a FOP mutation cascade.

Periorbital Myofibroma in a Child: A Case Report and Review of the Literature

Infantile myofibroma is a rare benign tumor usually diagnosed before the age of 2 and found in the head and neck but much more rarely in the orbital region. There have only been 7 cases of periorbital myofibromas reported in children in the literature to date. The current case is of an 8-year-old boy with a left upper eyelid myofibroma confirmed on histopathological and immunochemical analysis. A literature review of periorbital myofibromas has been performed to bring the reader up-to-date with the current understanding and management of the disease.

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.

The "myofibroblast" that is omnipresent in pathology and key to the EMT concepts does not actually exist, since normal fibroblasts contain stress fibril organelles (SMA bundles with dense bodies) variably detected by TEM and IHC: conclusions by a diagnostic pathologist with decades of ultrastructural experience

The so-called "enigmatic" unique "myofibroblast" has been erroneously substituted for virtually all things fibroblastic in soft tissue pathology and believed to be the ultimate fibrogenic cell. It is also internationally considered to be the mesenchymal cell in un-proven post-natal EMT, EMT organ/tissue fibrosis, and the assumption that EMT/MET is key to carcinoma/adenocarcinoma invasion and metastasis. However, no such cell exists, having been mistaken for our normal ubiquitous fibrogenic fibroblasts that contain peripheral bundles of actin (SMA) with dense bodies, i.e. stress fibril (SF) organelles variably detectable by TEM and SMA IHC, depending on the degree of activation. The only detectable features distinguishing what are erroneously believed to be two unique fibrogenic spindle cells are the SF. Is the variable detection of SF/SMA in fibroblastic and non-fibroblastic lesions significant? Carcinosarcomas are not bi-phasic malignancies or proof of EMT/MET. What does it mean that the fibroblasts of so-called "carcinoma-associated fibroblasts (CAF)" are not "myofibroblasts"? The true myofibroblast is the ultrastructurally and functionally unique, terminally-differentiated, pathognomonic cell of physiologic wound-healing, which unfortunately has been confused with the activated fibroblast. This study fails to demonstrate any ultrastructural evidence that either normal epithelial (EMT) or carcinoma/adenocarcinoma cells can undergo reversible transition into mesenchymal cells (EMT/MET) under any circumstances. The SF/SMA-positive fibrogenic cell in organ/tissue fibrosis is the genetically up-regulated, activated fibroblast, which has no relationship to EMT. Are any of the innumerable biochemical factors/elements considered to be associated with this non-existent cell and its related processes related to the activated fibroblast? The conclusions are based on review of every electron micrograph taken during a 40-year career in diagnostic and research ultrastructural pathology, and by confirming that the published TEM figures of so-called "myofibroblasts", are actually of fibroblasts.

Pediatric fibroblastic and myofibroblastic lesions

Fibrous lesions of infancy and childhood are a heterogeneous group of entities composed predominantly of fibroblasts and myofibroblasts, ranging from reactive lesions to neoplasms with a range of malignant potential. Although rare, their correct recognition by histopathology is important clinically as they exhibit a wide range of behaviors and may be associated with distinct underlying syndromes. Contributions from molecular diagnostics have enabled more accurate diagnosis, and have changed our concepts of some tumor types. In this review, we discuss the clinicopathologic spectrum of fibroblastic and myofibroblastic lesions of childhood and adolescence.

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

The authors address a group of loosely associated, characteristically benign soft tissue neoplasms that exhibit partial myoid differentiation. The entities share similarities in morphology and in nomenclature that have historically created confusion. The authors attempt to clarify the distinct architectural patterns and the corresponding immunophenotypic and ultrastructural features that distinguish myofibroma, myopericytoma, myoepithelioma, and myofibroblastoma.

Rapid regression of duodenal inflammatory myofibroblastic tumor after intravenous ketorolac: case report and review of the literature

Inflammatory myofibroblastic tumors are known to sometimes regress spontaneously or in response to treatment with antiinflammatory drugs. We present the case of a 13-year-old boy with an inflammatory myofibroblastic tumor of the proximal duodenum, which regressed rapidly within days of an open surgical biopsy, resulting in perforation of the duodenum. Ketorolac was administered intravenously after the biopsy and is implicated as a potential cause of the rapid regression of the tumor. We discuss the surgical management of this patient and present a review of the literature.

Oral myofibromas: report of two cases and review of clinical and histopathologic differential diagnosis

Myofibroma is a benign mesenchymal neoplasm composed of myofibroblasts which has been described with different synonyms since the first report in 1951. It may show clinical and histologic features that may be misinterpreted as a malignancy. We describe 2 cases of oral myofibromas affecting infants; the first one showed a rapid growth with teeth displacement and ulceration; the second one presented a relatively slow growth with an indolent course. Differential diagnosis included benign and malignant mesenchymal neoplasms, salivary gland tumors, and reactive processes. Microscopic analysis of both lesions revealed a spindle cell tumor with immunoreactivity for vimentin, muscle-specific actin, and specific smooth muscle isoform alpha-actin, rendering the diagnoses of myofibroma. The patients were treated with surgical excision, and both are in follow-up without any signs of recurrence. Myofibroma presents a wide range of differential diagnosis, including benign and malignant neoplasms. Therefore, accurate diagnosis may avoid an unnecessary aggressive therapy.