Fibrillar Stroma Research Articles

Oral Lipomatous Neurofibroma: A report of two cases and a review of the literature

Neurofibroma is a benign tumor that originates from the peripheral nerve sheath. This lesion may assume multiple growth patterns and various histologic variants have been described in the literature. We present two cases of lipomatous neurofibroma, a rare variant in the oral cavity. This variant is typically seen as a cutaneous lesion predominately located in the head and neck. Case 1 was a 62-year-old female who presented with a mass of her left posterior palate. Case 2 presented as a submucosal dorsal tongue mass in an 18-year-old male. Both lesions appeared clinically benign. Neither patient had a known history of neurofibromatosis type 1. The biopsies from case 1 and case 2 showed similar histopathological features. These two lesions were well delineated submucosal tumors characterized by an admixture of spindled neural cells and mature adipocytes. The mature adipocytes were separate from the regional adipose tissue. The spindle cells contained serpentine nuclei set in a wavy well-vascularized fibrillar stroma. The immunohistochemical staining for both lesions revealed S100 positivity of the tumor cells and negative staining for CD99, CD34, and BCL2. Differential diagnosis for these tumors included solitary fibrous tumor and spindle cell lipoma. However, based on the lack of a hemangiopericytoma-like vascular pattern, wire-like collagen and the pattern of IHC staining, these entities were excluded. While the diagnosis of a conventional neurofibroma is straightforward, the diagnosis of a lipomatous neurofibroma may be more challenging. Neither of our patients had a known history of Neurofibromatosis type 1 (NF1); however, cutaneous lipomatous neurofibromas have been associated with NF1. Therefore, a patient with a diagnosis of lipomatous neurofibroma should have a medical work-up to exclude this syndrome. With the presentation of two cases of lipomatous neurofibroma arising intraorally, we hope to raise awareness of this distinct and rare morphologic subtype of neurofibroma.

Fatal Hymenolepis nana cestodiasis in a ring-tailed lemur (Lemur catta).

The cestode Hymenolepis nana is a common parasite of humans and mice. Fecal shedding in the absence of clinical disease has previously been reported in ring-tailed lemurs (Lemur catta). This report describes fatal, disseminated H. nana cestodiasis infection in an aged ring-tailed lemur in a zoological collection. The parasites were associated with severe multifocal to coalescing and regionally extensive pyogranulomatous hepatitis and moderate multifocal pneumonia. The morphology of the parasites was highly unusual. Profiles were variably sized, ellipsoid to irregularly serpiginous, lined by a thin tegument, and filled with lightly eosinophilic fibrillar stroma and numerous, round basophilic cells. Polymerase chain reaction targeting a portion of the 18S rRNA gene and DNA sequencing of the amplicon showed 100% homology with H. nana.

Remodeling of extracellular matrix by normal and tumor-associated fibroblasts promotes cervical cancer progression.

BackgroundComparison of tissue microarray results of 29 cervical cancer and 27 normal cervix tissue samples using immunohistochemistry revealed considerable reorganization of the fibrillar stroma of these tumors.Preliminary densitometry analysis of laminin-1, α-smooth muscle actin (SMA) and fibronectin immunostaining demonstrated 3.8-fold upregulation of laminin-1 and 5.2-fold increase of SMA in the interstitial stroma, indicating that these proteins and the activated fibroblasts play important role in the pathogenesis of cervical cancer. In the present work we investigated the role of normal and tumor-associated fibroblasts.MethodsIn vitro models were used to throw light on the multifactorial process of tumor-stroma interaction, by means of studying the cooperation between tumor cells and fibroblasts. Fibroblasts from normal cervix and cervical cancers were grown either separately or in co-culture with CSCC7 cervical cancer cell line. Changes manifest in secreted glycoproteins, integrins and matrix metallo-proteases (MMPs) were explored.ResultsWhile normal fibroblasts produced components of interstitial matrix and TGF-β1 that promoted cell proliferation, cancer-associated fibroblasts (CAFs) synthesized ample amounts of laminin-1. The following results support the significance of laminin-1 in the invasion of CSCC7 cells: 1.) Tumor-associated fibroblasts produced more laminin-1 and less components of fibrillar ECM than normal cells; 2.) The production of laminin chains was further increased when CSCC7 cells were grown in co-culture with fibroblasts; 3.) CSCC7 cells were capable of increasing their laminin production; 4.) Tumor cells predominantly expressed integrin α6β4 laminin receptors and migrated towards laminin. The integrin profile of both normal and tumor-associated fibroblasts was similar, expressing receptors for fibronectin, vitronectin and osteopontin. MMP-7 secreted by CSCC7 cells was upregulated by the presence of normal fibroblasts, whereas MMP-2 produced mainly by fibroblasts was activated in the presence of CSCC7 cells.ConclusionsOur results indicate that in addition to degradation of the basement membrane, invasion of cervical cancer is accomplished by the remodeling of the interstitial stroma, which process includes decrease and partial replacement of fibronectin and collagens by a laminin-rich matrix.

Epithelioid schwannoma of the facial nerve masquerading as pleomorphic adenoma: A case report

Schwannomas arising in the parotid gland or peri-parotid region is frequently misdiagnosed as pleomorphic adenoma on cytologic preparations. The epithelioid variant of schwannoma is particularly susceptible to misdiagnosis because this neoplasm typically has epithelioid and spindled cells, which are associated with fibrillar stroma and mimic the epithelial, myoepithelial, and stromal components of a pleomorphic adenoma. Preoperative diagnosis of schwannoma is critical in order to plan appropriate management and to avoid inadvertent injury to the associated nerve during surgical resection. Thus, awareness of the distinct clinical, radiological, and cytomorphological features of schwannoma is important in order to guide clinical management. If the cytomorphological features are equivocal, immunohistochemical staining may provide a valuable alternative for distinguishing between pleomorphic adenoma and schwannoma.

In vivo evaluation of 13‐93 bioactive glass scaffolds with trabecular and oriented microstructures in a subcutaneous rat implantation model

The ability of two groups of 13-93 bioactive glass scaffolds to support tissue ingrowth was evaluated after implantation for 4 weeks into subcutaneous pockets in the dorsum of Fisher 344 rats. One group of scaffolds (porosity = 85%; pore size = 100-500 microm) had a "trabecular" microstructure similar to that of dry human trabecular bone, whereas the other group had a "columnar" microstructure of oriented pores (porosity = 65%; pore width = 90-110 microm). Despite the lower porosity and pore width, the columnar scaffolds supported abundant soft tissue ingrowth (glycosaminoglycan and fibrillar stroma), whereas the trabecular scaffolds showed only limited tissue ingrowth. When seeded with mesenchymal stem cells (MSCs), both groups of scaffolds supported abundant tissue infiltration. Bone-like tissue was formed in both groups of scaffolds seeded with MSCs, but not in the scaffolds without MSCs. The new tissues integrated with the hydroxyapatite-like surface layer of the scaffolds which resulted from the conversion of the bioactive glass in the body fluids. The results indicate that the trabecular bioactive glass scaffolds seeded with MSCs, as well as the columnar bioactive glass scaffolds, seeded with MSCs or unseeded, could serve as substrates for bone repair and regeneration.

Atypical Chordoid Structures in the Aristotle's Lantern of Regular Echinoids

AbstractRegular sea–urchins, as a rule, prepare and process their food as pellets in their buccal cavity before ingesting them. This is obtained through the synergistic interaction of the five teeth with five fleshy protuberances (paradental tongues) which extend into the oral cavity and work like tongues. Each of these structures consists of two anatomically distinct parts: the outer component is a deep pouch of the terminal tract of the pharynx and shows a histological organization similar to that usually shown by the pharyngeal wall itself. The deeper component (paradental axis) is represented by a supporting rod and shows a peculiar histological structure, which consists of glycogen containing vesiculate cells mixed to slim muscle fibres and held together by a thin fibrillar stroma. The paradental axes are very problematic structures in terms of comparative anatomy and phylogenetic aspects. Their microscopic and submicroscopic organization is unusual for an echinoderm and recalls that of different types of chordoid organs commonly found in other invertebrates (Protostomata and Deuterostomata).

A Quantitative Analysis of the Ultrastructural Organization of Extracellular Components in Human Articular Cartilage

Extracellular components of human articular cartilage have been studied using quantitative and ultrastructural methods. A new combination of electron microscopic, physicochemical, and mathematical methods has been proposed to study the structural organization of the fibrillar stroma, interfibrillar spaces, and structural proteoglycans. The new methodology has made it possible to isolate in the cartilage three layers with various types of spatial orientation of the fibrillar stroma. The summary volume and differential distribution of the interstitial microcirculatory channel have been derived. Proteoglycans of the integrative buffer metabolic medium have been identified using transmission and scanning electron microscopy. The data suggest a more accurate concept of the structural organization of human articular cartilage.

Cardiovascular complications of chronic catheterization of the jugular vein in the dog.

Cardiovascular changes associated with indwelling catheters were evaluated in 51 adult beagle dogs catheterized for 4 to 9 weeks. Pathologic changes consistent with traumatic injury were in the vena cava and endocardium of the right atrium of 88% of cannulated dogs. Lesions were characterized by surface denudation and diffuse intimal thickening due to myointimal hyperplasia and deposition of extracellular matrix. Affected intima was lined by hyperplastic, poorly differentiated endothelial cells and contained round to oval cells with characteristics of smooth muscle cells. After 9 weeks, thickened intima was vascularized and composed of spindle-shaped cells and fibrillar stroma. Intimal sclerosis and localized proliferative papillary projections in the vena cava cranial to areas of myointimal hyperplasia occurred infrequently. Traumatic lesions, regardless of location or severity, did not extend below the internal elastic membrane. Inflammatory cellular responses, when present, were minimal. The location, distribution, and morphogenesis of catheter-related cardiovascular lesions distinguishes them from those induced by chemical toxicity or pharmacotoxicity.