The Fibromatoses

Electron microscopy of juvenile nasopharyngeal angiofibroma: clinical and histopathological correlates

BACKGROUND

The histological and electron-microscopic (EM) characteristics of juvenile nasopharyngeal angiofibroma (JNA) have been described but no study has compared them with one another or with clinical features. The objective is to compare ultrastructural characteristics of JNA with clinical parameters.

METHODS

This prospective study included histology of 21 samples of which only 13 underwent transmission-EM. Four clinical parameters (age, duration, epistaxis, recurrence), three radiological-staging, 13 histological and 15 EM characteristics were considered. A descriptive analysis for association of these characteristics and also with clinical parameters was attempted. Furthermore statistical analysis of clinical and radiological categories with respect to frequencies of ultrastructural characteristics was also undertaken.

RESULTS

Dense-intranuclear-inclusions (DNI) and peripheral-nuclear-irregularities were universally encountered while other very prominent features were nuclear-blebs-and-pockets, myoid-features, thin-vessel-wall (TnVW), irregular-vascular-contour (IVC) and fibrous-stroma (FS). Statistical significance was obtained between recurrence with histology (p = 0.04) and Fisch staging with EM (p = 0.001). While muscle-in-vessel-wall, thick-vessel-wall, mast-cells, stellate-stromal-cells and cellular-stroma predominated in recurrent cases, the upfront disease showed predominance of scar-like-stroma, fusiform-stromal-cells, IVC, TnVW, FS, organised-collagen-bundles and less-cellular-stroma. A very unique Rod-like-structures were appreciated in the cytoplasm of the fibroblast for the first time.

CONCLUSIONS

While histological parameters of recurrence need further validation, a larger sample may better define histopathological surrogate for predicting intracellular dynamics that may further correlate with underlying cellular stresses. Hence an 'ultrastructural staging' may better customise treatment protocol and prognosis. Furthermore 'characteristic' unique rods need to be further investigated along with validation of viral aetiology for DNI.

Myofibroblastoma of the Chest Wall

We describe a case of myofibroblastoma of the soft tissue of the chest wall occurring in a 5-year-old boy. The lesion consisted of a proliferation of monomorphous spindle-shaped cells with interspersed extracellular matrix, arranged in interlacing fascicles. Immunohistochemically, neoplastic cells showed a diffuse cytoplasmic staining for vimentin and actin and a strong surface positivity for fibronectin. Ultrastructurally, the cytoplasm of tumor cells contained abundant rough endoplasmic reticulum cisternae and peripheral bundles of microfilaments with focal densities. In addition, several fibronexus junctions were identified. The combination of these histomorpliologic and ultrastructural features indicates myofibroblastic differentiation of neoplastic cells. We hypothesize that soft-tissue myofibroblastoma may be related to infantile hemangiopericytoma and infantile myofibromatosis, representing the final maturative step in a spectrum of lesions formed by myofibroblasts and pericytes in the more immature variants and exclusively by myofibroblasts in the more mature lesions. Int J Surg Pathol 0(0):00-00, 1996

Morphological characterization of skin ganglion-like cells in Djungarian hamsters (Phodopus sungorus)

Characteristic ganglion-like cell proliferation observed in the skin of Djungarian hamsters was investigated using 24 male and 24 female hamsters, 1-6 months of age, to examine the anatomic location of these ganglion-like cells and their morphologic features. One abdominal skin tumor composed of these cells and resembling proliferative fasciitis in humans was also examined. Skin ganglion-like cells were rarely observed in young animals but increased in number and extent with age, especially in males. These cells were frequently seen in the ventral and medial regions of the trunk and legs rather than in the dorsal and lateral regions. Light microscopic examination of these ganglion-like cells revealed abundant vesicular basophilic cytoplasm with delicate intracytoplasmic silver stain-positive fibrils. Ultrastructurally, these cells contained abundant rough endoplasmic reticulum and Golgi complexes with dilated cisternae; intracellular collagen fibrils were present within these cisternae. Heat shock protein 47, beta-tubulin, and androgen receptor were expressed in these cells. The morphologic features of cells of one tumor resembling human proliferative fasciitis were identical to those observed in ganglion-like cells. The results of the present study suggest that these ganglion-like cells are derived from intrinsic undifferentiated mesenchymal cells in the dermis or subcutaneous adipose tissue and that any tumor-like lesion they form should be regarded as an abnormal proliferative lesion of skin ganglion-like cells rather than as proliferative fasciitis or fibroma.

An ultrastructural study of lipodystrophia centrifugalis abdominalis infantilis, with special reference to fibrous long-spacing collagen

Lipodystrophia centrifugalis abdominalis infantilis (LCAI) in a 2.5-year-old Japanese girl is reported. Clinically she had a curved cutaneous depression with a slightly elevated erythematous border on the left abdomen beyond the left groin. The regional lymph node was palpable. Histologic examination showed a decrease of the fat, an inflammatory infiltrate mainly composed of lymphocytes, and septal fibrosis in the subcutaneous tissue. Immunohistochemical analysis found that infiltrating lymphocytes were mainly positive against CD4. Ultrastructurally nuclei in the adipocytes were crescent shaped and located toward the periphery of the cell. Some banded structures with a periodicity of 150 nm, and with intraperiodic bands, referred to as fibrous long-spacing collagen (FLSC), were observed in the septal area of the fatty tissue. These results indicated that FLSC was correlated with the breakdown of fibrillar collagens in LCAI.

Heterogeneity in the gingival fibromatoses

Forty-nine cases of isolated familial and idiopathic gingival fibromatoses, consisting of 12 cases from six families and 37 cases of idiopathic gingival fibromatosis, were reviewed. Pedigrees of five families revealed various penetrances and genetic heterogeneity as suggested by the presence of both autosomal dominant and autosomal recessive inheritances. Ultrastructurally, the lesions were composed of fibroblast-like cells and myofibroblast-like cells, with the former being the predominant cell type. The 267 cases of familial and idiopathic gingival fibromatoses were analyzed, and they with or without hypertrichosis, mental retardation, and/or epilepsy. These included 49 cases seen by the authors, 50 cases from the Japanese literature, and 168 cases from non-Japanese literature. Isolated gingival fibromatosis occurred more frequently after age of 12 years (P less than 0.0074). There was no significant difference in age of onset between generalized and localized forms of the idiopathic gingival fibromatosis. Gingival fibromatosis with hypertrichosis and mental retardation and/or epilepsy occurred frequently before 12 years (P less than 0.069). It has been shown that heterogeneity of the gingival fibromatosis is a result of either histologic heterogeneity, genetic heterogeneity, or a combination with other systemic disorders.

Inclusion body myofibroblasts other than those seen in recurring digital fibroma of childhood

Four patients of the toxic oil epidemic syndrome (TOES), which took place in Spain in 1981, showed a dermohypodermal fibroblastic process with round eosinophilic cytoplasmic inclusions (ECI) in the proliferating cells. Light and electron microscopic studies revealed that those cells had myofibroblastic features and that the ECI were identical to those seen in recurring digital fibroma of childhood (RDFC). Two cases of RDFC, involving the fingers of 6-month-old and 2-year-old patients, were examined by light and electron microscopy for comparative study. The 4 patients of TOES, aged 14 to 46 years, showed generalized sclerodermalike skin changes, and skin biopsies were obtained from the anterior wall of the abdomen and retromaleolar region of the left leg. The ultrastructural study of the ECI and the initiating changes leading to them allowed us to suggest a cytoskeletal origin for these inclusions.