Inflammatory Myofibroblastic Tumor of the Lung and the Maxillary Region: A Benign Lesion with Aggressive Behavior

Inflammatory myofibroblastic tumor (IMT) is a rare mass-forming lesion characterized by fibroblastic or myofibroblastic spindle cell proliferation with varying degrees of inflammatory cell infiltration. Although it has been reported in virtually every organ in the body, the lung is the most common site of involvement. Extrapulmonary IMTs, although rare, have been reported and are characterized by different, more aggressive behavior. We report an extremely rare case of maxillary metastases of pulmonary IMT. Lung IMT was initially misdiagnosed, and oral lesion mimicked clinically and radiologically a radicular cyst. On histologic examination, cells exhibited diffuse and intense immunoreactivity forα-smooth muscle actin and vimentin whereas both pulmonary and oral IMTs presented absence of cellular atypia and lack of expressivity of oncogenic determinants. Distant metastases of lung IMT are extremely unusual, and this is the first report to our knowledge with this particular clinical course. Despite the possibility that the present case could also represent a metachronous multifocal IMT, with pulmonary and extrapulmonary lesions, similar histopathological and immunohistochemical patterns in lung and maxillary region suggest a metastatic course.

Prostatic Stromal Hyperplasia With Atypia: Follow-up Study of 18 Cases

Context.—Prostatic stromal hyperplasia with atypia is a rare lesion that can be mistaken for sarcoma because of the presence of atypical, bizarre, degenerative myocyte nuclei. Objective.—To determine the diagnostic criteria and clinical significance of prostatic stromal hyperplasia with atypia. Design.—Eighteen cases of prostatic stromal hyperplasia with atypia were reviewed from the consultation file of one of the authors (D.G.B.). Results.—Prostatic stromal hyperplasia with atypia consists of 1 or more ill-defined, uncircumscribed, hyperplastic stromal nodules, with variable numbers of atypical, bizarre giant cells, with vacuolated nuclei, smudged chromatin, and frequent multinucleation infiltrating around benign acini. There was a hypocellular, loose, myxoid stromal matrix, with ectatic hyalinized vessels and mild to moderate chronic inflammation. Stromal cells displayed intense immunoreactivity for androgen receptors and vimentin, but moderate reactivity for desmin and actin. There were 3 local recurrences, with a mean follow-up of 6.3 years (range, 0.5–14 years), but none developed evidence of sarcomatous transformation or malignancy. Conclusions.—Prostatic stromal hyperplasia with atypia is a rare, benign lesion, composed of degenerative myocytes with atypia that is histologically and clinically reminiscent of benign counterparts in the myometrium, breast, vulva, vagina, and elsewhere. Recognition of this distinctive entity should allow separation from phyllodes tumor and sarcoma of the prostate. The phrase stromal tumor of uncertain malignant potential is inappropriate for this benign tumor, and its use is discouraged.

Eyelid Phakomatous Choristoma

Purpose To report a case of congenital phakomatous choristoma (PC) of the eyelid, a rare tumor of lenticular anlage in the subcutaneous tissue and dermis. Case A boy had a mass in the right lower eyelid near the inner canthus at birth. At age 10 months, the tumor was excised. Results The tumor cells showed intense immunoreactivity positive for S-100 protein, vimentin, and periodic acid-Schiff. Keratin markers, epithelial membrane antigen, glial fibrillary acidic protein, muscle specific actin, and epithelial membrane antigen were negative. The histopathologic features were consistent with those of a PC. Conclusions This histopathologic and immunoreactivity study supports the proposal that PC is a rare entity of lenticular anlage origin. Only 18 such cases have been described previously.

Myofibroblastoma in the suprasellar region

✓ Myofibroblastoma is a rare type of benign mesenchymal tumor; only two cases of intracranial myofibroblastoma have been reported in the literature. The authors report on the case of a 34-year-old woman with a myofibroblastoma in the suprasellar region who presented with the complaint of sudden onset of headache followed within 2 weeks by progressively worsening visual disturbance. Computerized tomography scanning demonstrated a mixed low- and high-density mass in the suprasellar region and contrast-enhanced magnetic resonance imaging revealed the mass to be of mixed intensity with heterogeneous enhancement. The tumor was subtotally removed via a right frontobasal translamina—terminalis approach and her vision improved immediately. Histologically, the tumor was characterized by alternating areas of spindle-shaped and round cells that were separated by collagen fibers. The diagnosis of myofibroblastoma was based on the tumor's intense immunoreactivity for α—smooth-muscle actin and the ultrastructural identification of myofibroblasts. The tumor was thought to have originated from the meninges in the suprasellar region.

Lysosomal cysteine and aspartic proteinases, acid phosphatase, and an endogenous cysteine proteinase inhibitor, cystatin-beta, in rat osteoclasts.

To understand the bone resorption and lysosomal proteinases in osteoclasts, we examined by immunohistochemistry the localization of lysosomal cysteine and aspartic proteinases, acid phosphatase, and cystatin-beta in the rat tibial bone. Immunoreactivity for cathepsins B, C, H, and L, cathepsin D, acid phosphatase, and cystatin-beta was demonstrated in various cells of the bone tissue; in particular, large multinucleated osteoclasts attached to the bone surface and chondroclasts in the proximal growth plate. These cells showed intense immunoreactivity for these lysosomal enzymes and cystatin-beta. Bone surface-lining osteoblasts displayed distinct immunoreactivity for cathepsins B, C, D, H, and acid phosphatase, while osteocytes often exhibited that for cathepsins D, H and acid phosphatase. Chondrocytes in the growth plate demonstrated intense immunoreactivity for cathepsins B, D, and acid phosphatase. Immunoreactivity for cystatin-beta was detected in osteoclasts and chondroclasts only. Large, round multinucleated cells free from the bone surface exhibited weak, faint, or no immunoreactivity for the lysosomal enzymes and cystatin-beta. These results suggest that lysosomal cysteine and aspartic proteinases may play a role in the degradation of organic constituents of the bone matrix. Moreover, cystatin-beta can serve as an excellent marker protein for osteoclasts.

Developmentally regulated expression of alpha 6 integrin in avian embryos

The distribution pattern of the avian alpha 6 integrin subunit was examined during early stages of development. The results show that this subunit is prevalent in cells of the developing nervous system and muscle. alpha 6 is first observed on neuroepithelial cells of the cranial neural plate and trunk neural tube. With time, immunoreactivity becomes prominent near the lumen and ventrolateral portions of the neural tube, co-distributing with neurons and axons, particularly notable on commissural neurons. The alpha 6 expression pattern is dynamic in the neural tube, with immunoreactivity peaking by embryonic day 6 (stage 30) and decreasing thereafter. The ventral roots and retina exhibit high levels of immunoreactivity throughout development. In the peripheral nervous system, alpha 6 immunoreactivity first appears on a subpopulation of sympathoadrenal cells around the dorsal aorta and later in the dorsal root ganglia shortly after gangliogenesis. Immunoreactivity appears on prospective myotomal cells as the somites delaminate into the dermomyotome and sclerotome, remaining prominent on myoblasts and differentiated muscle at all stages. The mesonephros also has intense immunoreactivity. In the periphery, alpha 6 immunoreactive regions often in proximity to laminin, which is thought to be the ligand of alpha 6 beta 1 integrin.

Cell Kinetics and Tumor-Associated Antigen Expression in Human Mammary Carcinomas

Twenty-six primary breast carcinomas were studied to evaluate cell proliferation as assessed by thymidine labeling index (TLI), and antigenic phenotype, as defined by immunohistochemistry using eight monoclonal antibodies (MAbs) to tumor-associated antigens (TAAs). The majority of tumors had low TLI values. Reactivity to MAbs B72.3, CC49, CC83 (anti TAG 72), COL-12 (anti CEA) and MOv2 (against a tumor-associated mucoprotein) was restricted to < 50% of the tumors studied, while MAbs B1.1 (anti CEA), MBrl and MBr8 (to tumor-associated carbohydrates) reacted with > 50% of the cases. Correlations between expression of TAAs and proliferative activity showed that the tumors could be divided into three groups, two characterized by either high proliferative activity and absence of antigenic expression or low proliferative activity and strong antigenic expression, and the third showing no relation between these two biological features. We defined two antigenic phenotypes associated with specific cellular kinetics: one characterized by negative immunoreaction with MAbs, CC49, CC83 and COL-12 and high proliferative activity; the other characterized by intense immunoreactivity with these antibodies and low proliferative activity. The data suggest that cell proliferation and antigenic phenotype may define biologic subsets of breast carcinomas

Immuno-ultrastructural localization of sodium channels at nodes of Ranvier and perinodal astrocytes in rat optic nerve

Immuno-electron microscopic localization of sodium channels at nodes of Ranvier within adult optic nerve was demonstrated with polyclonal antibody 7493. The 7493 antisera, which is directed against purified sodium channels from rat brain, recognizes a 260 kDa protein in immunoblots of the crude glycoprotein fraction from adult rat optic nerve. Intense immunoreactivity with 7493 antisera was observed at nodes of Ranvier. Axon membrane at the node was densely stained, whereas paranodal and internodal axon membrane did not exhibit immunoreactivity. The axoplasm beneath the nodal membrane displayed variable immunostaining. Neither terminal paranodal oligodendroglial loops nor oligodendrocyte plasmalemma were immunoreactive with 7493 antisera. However, perinodal astrocyte processes exhibited intense immunoreactivity with the anti-sodium channel antisera. Optic nerves incubated with pre-immune sera, or with 7493 antisera that had been pre-adsorbed with purified sodium channel protein, displayed no immunoreactivity. These results demonstrate localization of sodium channels at high density at mammalian nodes of Ranvier and in some perinodal astrocyte processes. The latter observation offers support for an active role for perinodal astrocyte processes in the aggregation of sodium channels within the axon membrane at the node of Ranvier.

Histochemical detection of osteocalcin in normal and pathological human bone.

We investigated the immunohistochemical localization of osteocalcin in demineralized, paraffin-embedded normal and pathological human bone. Acid decalcification protocols appeared to be more suitable for osteocalcin detection than mild chelating agents. In normal lamellar bone, osteocalcin was detected in osteocytes and along the lamellar bone matrix in fine granular deposits. Under pathological conditions (osteomyelitis, neoplasia), appositional bone showed immunoreactivity in osteoblasts and osteocytes but not in the provisory woven bone matrix. Intense immunoreactivity could be seen at the cell borders of osteoclasts and the bone margins of Howship lacunae. In primary bone-forming tumors, osteocalcin immunoreactivity was detected in osteoblasts and their malignant counterparts. On the basis of these results, we conclude that optimal preservation of osteocalcin is obtained through mild acid decalcifiers. Osteocalcin is deposited in bone matrix, especially that of metabolically inactive bone. In neoplasms, osteocalcin could be a marker of osteoblastic differentiation.