John W. Bolen

Reactive and neoplastic serosal tissue. A light-microscopic, ultrastructural, and immunocytochemical study.

Normal and reactive non-neoplastic serosal tissues and a spectrum of serosal neoplasms were studied using lightmicroscopic, ultrastructural, immunocytochemical, gel electrophoretic, and immunoblot techniques. Normal surface mesothelium expressed both low- and high-molecular- weight cytokeratins, whereas the scattered submesothelial cells were decorated only with antibodies to vimentin. Reactive non-neoplastic subserosal cells, however, coexpressed both low-molecular-weight cytokeratin and vimentin and demonstrated the ability for surface differentiation during which higher-molecular-weight cytokeratins were acquired and vimentin was lost. The authors suggest the term “multipotential subserosal cells,” recognizing the unique intermediate filament expression of reactive subserosal cells and the ability for surface differentiation. The intermediate filament expression of the sarcomatoid/desmoplastic mesotheliomas resembled the MSC, whereas epithelial mesotheliomas resembled surface mesothelium. These findings have potential usefulness for diagnostic pathology.

Peripheral neuroepithelioma: a light and electron microscopic study.

A primitive neuroectodermal tumor of peripheral nerve origin was examined by light and electron microscopy. The lesion arose in association with the SI nerve root of the lumbosacral plexus in a 22‐year‐old female. Following a surgical biopsy, the patient received systemic chemotherapy; however, approximately one‐and‐a‐half years later, she suffered a clinical relapse with locally recurrent tumor. An excisional biopsy was performed, and pathologic examination revealed progressive neuroblastic differentiation. The ultrastructural features of neoplastic Homer‐Wright rosettes will be illustrated, and the non‐specificity of cytoplasmic glycogen in the evaluation of „small round cell neoplasms”︁ will be emphasized.

Enchondromatosis (Ollier's disease) and ovarian juvenile granulosa cell tumor. A case report and review of the literature

An ovarian juvenile granulosa cell tumor in a 15‐year‐old white girl is reported. The patient had enchondromatosis (Olliers disease), and a reivew of the literature revealed two previous reports linking enchondromatosis with ovarian sex‐cord stromal tumors. This heretofore unrecognized association between these two unusual lesions indirectly supports a generalized mesodermal dysplasia in patients with enchondromatosis. It also draws attention to the possible emergence of ovarian neoplasms in addition to the more frequently encountered chondrosarcomas.

Cutaneous T-cell Lymphoma: Evaluation of Pretreatment Skin Biopsy Specimens by a Panel of Pathologists

BACKGROUND AND DESIGN Cutaneous T-cell lymphoma (CTCL) frequently presents a difficult diagnostic challenge for the clinician and pathologist. To assess the diagnostic validity of conventional histopathologic findings in CTCL, pretreatment skin biopsy specimens were scored prospectively and independently by a panel of five to seven dermatopathologists and pathologists. Scores were compared with disease outcome. Repeatability of these scores was examined among observers and for the same observer. The study population consisted of 165 subjects, initially referred for suspected mycosis fungoides or Sézary syndrome. Ninety-two patients determined to have CTCL have been followed up for 6.3 +/- 3.5 years (mean +/- SD) and are categorized according to disease outcome: 22 are in complete remission, 35 are in partial remission, three have progressive lymphoma, 15 died of disease, 13 died of other causes, and four were unavailable for follow-up. Seventy-three patients determined not to have CTCL have been followed up for 5.3 +/- 3.2 years without subsequent clinicopathologic evidence of CTCL. These longitudinal data allowed comparisons of the clinical course with the original histologic interpretations. RESULTS Data showed that the histologic scores rendered by the pathology panel did not correlate with stage of disease and were not an accurate predictor of clinical outcome, because the histologic ratings did not discriminate between patients who eventually had complete remission and those with either progressive lymphoma or who have died of disease. The results also substantiate the low inherent reliability of histopathologic findings in CTCL. Large differences existed among pathologists in scoring the study populations and repeated reading of selected cases by the same panel member resulted in a change of diagnosis 15% of the time. Among the histologic features evaluated, only the presence of mitoses in the infiltrating cells showed a trend toward an unfavorable outcome. CONCLUSION Pathologic diagnosis in the CTCL disease spectrum should be interpreted with caution and then only in conjunction with the clinical evaluation. As expected, the use of an average value from a panel of readers added a component of stability to the histologic interpretation.

Serosal Tissue: Reactive Tissue as a Model for Understanding Mesotheliomas

Serosal tissues consist of a surface mesothelial layer and subsurface spindled connective tissue cells. Surface cells are decorated with antibodies to both low and high molecular weight cytokeratin whereas subserosal cells only express the intermediate filament vimentin. Serosal injury results in the proliferation of multipotential subserosal cells (MSC) which have the ultrastructural morphology of myofibroblasts and yet co-express low molecular weight cytokeratin and vimentin. These cells appear responsible for the re-establishment of surface mesothelium during which they acquire high molecular weight cytokeratin and loose vimentin. There are many parallels between reactive and neoplastic serosal tissues. Desmoplastic/sarcomatoid mesotheliomas resemble the MSC and co-express low molecular weight cytokeratin and vimentin and epithelial mesotheliomas resemble surface mesothelium and express both low and high molecular weight cytokeratin. The ability of normal serosal tissue to modulate its cell shape and intermediate filament expression helps understand the diversity of serosal tumors.

Mesotheliomas. A light- and electron-microscopical study concerning histogenetic relationships between the epithelial and the mesenchymal variants

Mesotheliomas have variable histological patterns which may suggest a predominance of epithelial cells, a predominance of mesenchymal cells, or a mixture of epithelial and mesenchymal cells. An adenomatoid tumor of the testis, a fibrous mesothelioma, and an epithelial mesothelioma were studied by light and electron microscopy to search for evidence of a histogenetic link between the various cell types. Each neoplasm was composed of poorly differentiated spindle-shaped cells and variably differentiated cells having epithelial, mesenchymal, and combined epithelial and mesenchymal features. The differentiated neoplastic cells exhibited a spectrum of cytodifferentiation with typical mesothelial cells at one end, typical fibroblasts at the other end, and trasitional forms in between. These observations are presented in detail as morphological evidence for a direct histogenetic relationship between the epithelial-appearing cells and the mesenchymal-appearing cells of human mesothelial neoplasms.

Spindle-cell lipoma. A clinical, light- and electron-microscopical study

Five spindle-cell lipomas, all in male patients, were examined by light and electron microscopy. Four were located in the subcutaneous tissues of the upper back or posterior neck and one behind the left ear. They exhibited a spectrum of histological growth patterns. Electron microscopy demonstrated two distinct populations of tumor cells; one, a spindled non-fat-storing mesenchymal cell and the other a mature lipocyte. It is hypothesized that the spindled cells are analogous to the stellate mesenchymal cell of the primitive fat lobule.

Ultrastructural and Immunohistochemical Features of Common Lung Tumors: An Overview

Lung cancer is rapidly becoming the most commonly diagnosed malignant neoplasm in the world. Pathologists play a key role in the care of patients with lung cancer by accurately classifying and staging these neoplasms. Immunohistochemistry and electron microscopy have become important tools in the diagnosis of lung tumors, especially those which are histologically undifferentiated. This review discusses the ultrastructural and immunohistochemical features of common lung tumors, with an emphasis on their diagnostic usefulness.

Benign lipoblastoma and myxoid liposarcoma: A comparative light-and electron-microscopic study

ABSTRACTA benign lipoblastoma and a myxoid liposarcoma were studied by light and electron microscopy. Both of these neoplasms had prominent plexiform vascular networks, early acquisition of fat by vascular pericytes, and progressive accumulation of fat by cells located away from the vasculature. Their component cells had investing basal laminae, pinocytotic vesicles, and cytoplasmic glycogen stores as well as cytoplasmic lipid. The process of neoplastic lipogenesis and the structural features of the neoplastic cells in both neoplasms resembled those of developing non-neoplastic fat tissue. The benign lipoblastoma appears to be analogous to developing fat, while the myxoid liposarcoma appears to recapitulate the actively proliferating zone of developing fat. The relationship between proliferating cells and the plexiform vascular network in all three processes is emphasized. We hypothesize that the vascular pericyte serves as a source for new fat storing cells.