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Increased Cellularity (increased + cellularity)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Cutaneous Congenital Plexiform Cellular Schwannoma: A Simulant of Malignant Peripheral Nerve Sheath Tumor of Childhood , A Case Report and Literature Review

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005
M. Matthews
Cutaneous plexiform schwannoma is a rare multilobulated variant of benign schwannoma. When presenting as the cellular subtype with significantly increased proliferative rate, diagnostic consideration of a malignant peripheral nerve sheath tumor is prompted. However, follow up demonstrates a benign natural history with propensity for local recurrence and typical lack of association with neurocutaneous syndromes. These lesions most commonly occur as cutaneous and subcutaneous masses of the extremities in the first four decades. Only 9 cases of congenital tumors are reported. A case of congenital plexiform cellular schwannoma, presenting as a cutaneous mass measuring 3.5 × 2.5 × 2.0 cm, excised from the left upper arm of a 16 month old female is discussed. Regions of increased cellularity and proliferation co-localized and were unassociated with nuclear anaplasia. Mitotic figures numbered 7 per 10 400x fields. The tumor cells were strongly immunoreactive for S-100 protein. The MIB-1index was multifocally 25% and p53 protein over expression was present in 50% of nuclei. Following excision with free margins the tumor locally recurred after 16 months. The recurrence was morphologically identical to the original lesion. Recognition of the clinical and morphological characteristics of this rarely encountered benign neoplasm will facilitate in diagnosing this entity. [source]

Histological analysis of achilles tendons in an overuse rat model

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2008
Mark A. Glazebrook
Abstract The purpose of this study was to design an animal model that induces histological changes in Achilles tendons consistent with those cited in the literature for human Achilles tendon disease. Sprague-Dawley rats were subjected to 10° uphill treadmill running on a custom-designed rodent treadmill and at a speed of 17 meters per minute for 1 h, five times per week, over a 12-week treatment period. Subsequent histological analysis revealed alterations in the rat Achilles tendon that were generally consistent with those described in the literature for diseased human tendon tissues. These features include: decreased collagen fiber organization, more intense collagen staining, and increased cell nuclei numbers. Interestingly, though, immunohistochemical cell typing suggests that the observed increased cellularity does not include a significant inflammatory component but is secondary to increased numbers of endothelial cells (i.e., vascularization) and fibroblasts. These histological features likely represent a biological repair/remodeling response resulting from overuse running. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:840,846, 2008 [source]

Multifocal dysembryoplastic neuroepithelial tumor with signs of atypia after regrowth

NEUROPATHOLOGY, Issue 4 2007
Jens Schittenhelm
We report the case of a multifocal dysembryoplastic neuroepithelial tumor (DNT) in a 7-year-old girl with local tumor regrowth 6 years later. The tumor was localized in the right parietal lobe extending from the cortex into the periventricular white matter. After subtotal resection of a histopathologically confirmed DNT we observed unexpected tumor progression in long-term follow-up. Therefore, a second surgery was performed when the patient was 14 years of age. In neuropathological examination of the second specimen the tumor showed an increased cellularity and pleomorphism, microvascular proliferations, an elevated proliferative activity (MIB1-index focally up to 10%) and cellular atypia not typical for WHO grade I DNT. Furthermore, MRI studies showed additional supratentorial and infratentorial lesions which remained stable over years and are also well consistent with DNTs. Thus, an unusual form of a DNT with multifocal lesions, local regrowth and morphological transformation is supposed. [source]

WT1 Is Not a Reliable Marker to Distinguish Reactive from Neoplastic Astrocyte Populations in the Central Nervous System

BRAIN PATHOLOGY, Issue 6 2010
T. David Bourne MD
Abstract A diagnostic difficulty in neuropathology practice is distinguishing reactive from neoplastic astrocyte populations. This is particularly true in small biopsy samples that lack evidence of increased cellularity or mitotic activity, microvascular proliferation, or necrosis. We performed the current study to validate the previously reported finding that in the central nervous system, the expression of WT1 is limited to neoplastic astrocytes. We retrospectively studied WT1 protein expression by immunohistochemistry (IHC) in 100 formalin-fixed, paraffin-embedded brain tissue samples consisting of 3 normal control tissues, 44 cases of reactive gliosis, 49 gliomas and 4 lesions suspicious for glioma. In normal human cortex, WT1 staining was restricted to vascular endothelium. Most cases of reactive gliosis (82%) showed at least focal WT1 positivity, and analysis of specimens with electrode monitoring lesions showed an inverse relationship between WT1 expression intensity and the number of days from electrode placement to tissue resection. All glioma samples (100%) and all cases suspicious for glioma (100%) showed at least focal WT1 positivity. Our results likely differ from those in the prior report because of differences in tissue fixation and IHC methodology. Thus, our findings indicate that WT1 expression alone is not a reliable feature to distinguish reactive from neoplastic astrocytes. [source]