Contribution of Electron Microscopy of Cell Cultures to the Classification of Three Round Cell Sarcomas in Children

We have studied three round cell sarcomas from pediatric patients in tissue culture to compare the electron microscopic morphology of cells in culture to cells from original biopsy specimens. None of the original tumors displayed distinctive features by light microscopy that would allow classification of a specific tumor type, and electron microscopy was not helpful in identifying specific morphologic features that would allow further classification of tumor types. However, electron microscopy of cells in culture from the three neoplasms revealed distinctive morphologic features that did allow further classification of all three tumors. Cells from an inguinal lymph node, which were cultured in soft agar tumor colony-forming assay, revealed Z-bands and actin and myosin filaments indicative of a rhabdomyosarcomatous nature for the tumor. Cells from 5-day, 10-day, and 4-month cultures of a bone marrow metastasis of a second tumor revealed features of skeletal muscle in the young cultures and neuroblasts in the older culture, suggesting a primitive neuroectodermal neoplasm. Cultured cells from the third tumor, a neoplasm of the calf in an infant, displayed large lakes of glycogen, typical of cells of Ewing's sarcoma, which were not present in the cells examined from the original lesion. Ultrastructural studies of cells in culture have the potential to add morphologic data that may be useful to further define and classify a neoplasm, as illustrated in the 3 cases reported here.     

Contribution of Electron Microscopy of Cell Cultures to the Classification of Three Round Cell Sarcomas in Children

We have studied three round cell sarcomas from pediatric patients in tissue culture to compare the electron microscopic morphology of cells in culture to cells from original biopsy specimens. None of the original tumors displayed distinctive features by light microscopy that would allow classification of a specific tumor type, and electron microscopy was not helpful in identifying specific morphologic features that would allow further classification of tumor types. However, electron microscopy of cells in culture from the three neoplasms revealed distinctive morphologic features that did allow further classification of all three tumors. Cells from an inguinal lymph node, which were cultured in soft agar tumor colony-forming assay, revealed Z-bands and actin and myosin filaments indicative of a rhabdomyosarcomatous nature for the tumor. Cells from 5-day, 10-day, and 4-month cultures of a bone marrow metastasis of a second tumor revealed features of skeletal muscle in the young cultures and neuroblasts in the older culture, suggesting a primitive neuroectodermal neoplasm. Cultured cells from the third tumor, a neoplasm of the calf in an infant, displayed large lakes of glycogen, typical of cells of Ewing's sarcoma, which were not present in the cells examined from the original lesion. Ultrastructural studies of cells in culture have the potential to add morphologic data that may be useful to further define and classify a neoplasm, as illustrated in the 3 cases reported here.     

Malignant Melanoma of Soft Parts: An Ultrastructural Study of Four Cases

Samples from three clinically functional retroperitoneal paragangliomas were studied by light and electron microscopy. The tumors exhibited a Zellballen pattern histologically, and ultrastructurally all three neoplasms consisted of cells containing catecholamine granules. Prominent cytoplasmic crystalloids were present in all cases. The crystalloids were identified in routine histologic sections, demonstrated eosinophilia, and stained with periodic acid-Schiff, Giemsa, phloxine-tartrazine, and azan stains. Ultrastructurally the crystalloids were osmiophilic, often appeared as slender needles, were membrane bound, and demonstrated a periodicity of 9 nm. The crystalloids, unlike the catecholamine granules, were negative for catecholamine fluorescence. X-ray microanalysis, however, revealed the selective presence of chromium in both catecholamine granules and crystalloids.     

恶性小圆细胞肿瘤免疫组织化学及病理组织学分析

本文分析57例恶性小凶细胞肿瘤(MSRCT)免疫组化表型及病理形态。结果表明:兔抗鸡结蛋白及(或)兔抗人肌红蛋白可作为横纹肌肉瘤的标志;神经母细胞瘤、嗅神经母细胞瘤及原始外周神经外胚层瘤的免疫组化特征为NSE阳性,而Vim阴性;抗NSE抗血清特异性差,其他MSRCT亦可与之反应。尤文肉瘤Vim阳性,有些病例NSE阳性。未分化滑膜肉瘤Vim阳性;部分病例Ker及(或)EMA阳性,可有假阴性。LCA是恶性淋巴瘤特异性标记。α_1-ACT对MSRCT鉴别诊断无价值。     

Malignant Fibrous Histiocytoma of Soft Parts: An Ultrastructural Quantitative Study

Thirty-two cases of soft tissue malignant fibrous histiocytoma (MFH), including 24 of common storiform-pleomorphic type, 7 of myxoid type, and 1 of inflammatory type, were analyzed in an ultrastructural quantitative study, the objective being to clarify the cellular composition and distribution of the tumor. Approximately 100 unselected cells in each tumor were classified into seven types as follows: undifferentiated (10%-62%, m: 29%), histiocytelike (8%-69%, m: 37%), fibroblastlike (0.9%-26%, m: 11%), myofibroblasts (0%-22%, m: 3%), intermediate between histiocytelike and fibroblastlike cells (1%-41%, m: 15%), multinucleated giant (0%-1%), and xanthomatous cells (0%-1%). The undifferentiated, histiocytelike, fibroblastlike, and intermediate cells constituted the principal types, invariably present, although in varying proportions in each tumor. No statistical difference in ultrastructural cellular composition was evident in different portions of the same tumor, and such was also the case between the two main subtypes of MFH, common and myxoid. Naphthyl thiol acetate (NTA) esterase was demonstrated in fibroblastlike cells, using the ultrastructural cytochemical technique, in both cases examined. The possibility that MFH may be of alternative undifferentiated mesenchymal cell origin has to be considered.     

Malignant Fibrous Histiocytoma of Soft Parts: An Ultrastructural Quantitative Study

Thirty-two cases of soft tissue malignant fibrous histiocytoma (MFH), including 24 of common storiform-pleomorphic type, 7 of myxoid type, and 1 of inflammatory type, were analyzed in an ultrastructural quantitative study, the objective being to clarify the cellular composition and distribution of the tumor. Approximately 100 unselected cells in each tumor were classified into seven types as follows: undifferentiated (10%-62%, m: 29%), histiocytelike (8%-69%, m: 37%), fibroblastlike (0.9%-26%, m: 11%), myofibroblasts (0%-22%, m: 3%), intermediate between histiocytelike and fibroblastlike cells (1%-41%, m: 15%), multinucleated giant (0%-1%), and xanthomatous cells (0%-1%). The undifferentiated, histiocytelike, fibroblastlike, and intermediate cells constituted the principal types, invariably present, although in varying proportions in each tumor. No statistical difference in ultrastructural cellular composition was evident in different portions of the same tumor, and such was also the case between the two main subtypes of MFH, common and myxoid. Naphthyl thiol acetate (NTA) esterase was demonstrated in fibroblastlike cells, using the ultrastructural cytochemical technique, in both cases examined. The possibility that MFH may be of alternative undifferentiated mesenchymal cell origin has to be considered.     

Intra-abdominal Desmoplastic Small Round Cell Tumor of the Peritoneum in a Young Man

The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors.     

Intra-abdominal Desmoplastic Small Round Cell Tumor of the Peritoneum in a Young Man

The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors.     

Glycogen-rich Clear Cell Carcinoma of the Urethra: An Ultrastructural Study

A 49-year-old black woman developed a urethral glycogen-rich clear cell carcinoma. She was treated with anterior pelvic exenteration. The resected lymph nodes, vagina, uterine cervix, endometrium, ovaries, and urinary bladder were free of neoplasm. Histologically the neoplasm consisted of clear cells growing in sheets and occasional papillary structures. In some areas, hobnail cells were present. Ultrastructurally, the cells had apical caps, short microvilli, and complex cell bases, and contained abundant glycogen. These features were identified in one, but not the other of two previously reported cases. Because glycogen-rich clear cell carcinomas of the lower urinary tract do not resemble ultrastructurally mesonephric remnants or carcinomas known to arise from them, these glycogen-rich clear cell carcinomas should not be called “me-sonephromas” as has been the practice.     

Glycogen-rich Clear Cell Carcinoma of the Urethra: An Ultrastructural Study

A 49-year-old black woman developed a urethral glycogen-rich clear cell carcinoma. She was treated with anterior pelvic exenteration. The resected lymph nodes, vagina, uterine cervix, endometrium, ovaries, and urinary bladder were free of neoplasm. Histologically the neoplasm consisted of clear cells growing in sheets and occasional papillary structures. In some areas, hobnail cells were present. Ultrastructurally, the cells had apical caps, short microvilli, and complex cell bases, and contained abundant glycogen. These features were identified in one, but not the other of two previously reported cases. Because glycogen-rich clear cell carcinomas of the lower urinary tract do not resemble ultrastructurally mesonephric remnants or carcinomas known to arise from them, these glycogen-rich clear cell carcinomas should not be called “me-sonephromas” as has been the practice.     

Electron Microscopy in the Diagnosis of Small Round Cell Tumors of Bone

Small round cell tumors involving bone can present problems in differential diagnosis by light microscopy. In exploring the role of electron microscopy in this situation, seven small cell osteosarcomas and seven mesenchymal chondrosarcomas were examined by electron microscopy and compared with typical and atypical Ewing's sarcomas. There is much overlap in the ultrastructural features of these tumors, but electron microscopy is helpful to establish or confirm a diagnosis of typical Ewing's sarcoma and, if representative matrix is present, of small cell osteosarcoma.     

Small round blue cell sarcomas of bone: an update on classification,pathology and molecular profiling

Small round cell sarcomas of bone are extremely aggressive tumors, most often occurring in children and young adults. Recent genomic discoveries have contributed to the current classification of these tumors. The latest edition of the WHO Classification of Tumors of Soft Tissue and Bone identifies four subcategories each with distinct clinical features and prognostic outcome- Ewing sarcoma with ETS rearrangements and tumors with gene fusions involving EWSR1-non-ETS, CIC -rearranged tumors and sarcoma with BCOR genetic alterations. This chapter focuses on pathological findings of these entities with particular emphasis on the molecular characteristics to enable accurate classification and appropriate patient management.     

Malignant Melanoma of Soft Parts Involving the Head and Neck Region: Review of Literature and Case Report

Malignant melanoma of soft parts (MMSP) was originally described as a distinct entity by Enzinger in 1965 and was termed “clear cell sarcoma of tendons and aponeuroses” because of its association with tenosynovial structures. It has been shown immunophenotypically and ultrastructurally that this tumor is derived from neuroectoderm and shares a number of features with cutaneous melanoma. Over 95% of MMSPs present in the extremities, with the head and neck region (1.9%) being an unusual site. This study presents an additional case of MMSP of the head and neck region involving the posterior cervical region in a 15-year-old Hispanic male and reviews the literature on MMSP. Ultrastructural examination showed rudimentary cell attachments, smooth cell membranes, discontinuous basal lamina, scanty glycogen, and occasional premelanosomes in some tumor cells. Cytogenetic analysis showed a reciprocal translocation between the long arms of chromosomes 12 and 22 [t(12:22)(q13;q12.2)], characteristic for MMSP and not seen in cutaneous melanoma. Survival in MMSP has been correlated with tumor size, tumor necrosis, and ploidy status. Overall reported clinical outcome for this tumor is as follows: died of disease, 45%; alive with disease, 23%; no evidence of disease, 30%; and died of other causes, 2%. MMSP represents a distinct entity with a characteristic ultrastructural appearance and a tumor defining cytogenetic translocation.     

Small Cell Neuroendocrine Carcinoma of the Urinary Bladder: Report of Three Cases with Ultrastructural Analysis

Three cases of small cell neuroendocrine carcinoma of the urinary bladder were studied by light and electron microscopic techniques. Dense-core, membrane-bound granules were identified in the cytoplasm of all 3 cases, substantiating the light microscopic impression of a morphologic similarity to other neuroendocrine carcinomas, such as small cell (oat cell) carcinoma of the lung. Two of the three cases showed clinical evidence of distant metastases, suggesting an aggressive biologic potential of this tumor similar to oat cell carcinoma of the lung. A partial remission was induced in these 2 cases using chemotherapy protocols similar to the drug regimens for small cell (oat cell) carcinomas of the lung. Recognition of this distinct entity has important clinical implications regarding therapeutic approach.     

上皮性标记物在人肺小细胞癌免疫组化研究中的应用

为证实肺小细胞癌的上皮特性,以上皮性标记物角蛋白(KT,细胞角蛋白(CKT),上皮性膜抗原(EMA),分泌成份(SC),糖脂类抗原(SLX)、糖脂类抗原(SLEA)、癌胚抗原(CEA)等用于本实验中。人肺两型小细胞癌(燕麦细胞癌和中间细胞型小细胞癌)均不同程度地表达了这些抗原,显示其上皮性分化的特性。根据抗原的阳性率和在细胞内存在形式不同,提示中间细胞型小细胞癌在生物学和组织学上更类似于腺癌和鳞癌的特征。上皮性膜抗原是小细胞癌较理想的标记物,而联合应用这些标记物能够增强诊断的准确性及评价标本的质量。     

Cell and Tissue Interactions of Treponema pallidum in Primary and Secondary Syphilitic Skin Lesions: An Ultrastructural Study of Serial Sections

There are limited reports on the ultrastructure of syphilis skin lesions. The aim of this study has been to perform an electron microscopic investigation of the morphology and the tissue distribution of treponemes in primary and secondary cutaneous lesions. Three cases of primary syphilitic chancre and one case of secondary syphilis were included. Prominent epidermal abnormalities in the primary chancre and a perivascular inflammatory infiltrate in the secondary lesion were found by light microscopy. Ultrastructurally, spirochetes were located mainly in the blood vessel walls and dermal tissue of the chancre lesions. In the secondary syphilis case, spirochetes were more abundant between epidermal keratinocytes. Most of them adjusted to the intercellular spaces. Occasionally, the electron microscopy images were highly suggestive of an intracellular location. Both the ultrastructural and immunohistochemical examination of the primary and secondary syphilis lesions showed a paradoxical distribution of the causative microorganisms compared to the light microscopic changes. In addition, the ultrastructural findings strongly suggest that Treponema pallidum subspecies pallidum invades tissues, not only through an intercellular, but also through a transcellular pathway.     

Primary Small Cell Neuroendocrine Carcinoma of the Kidney: Morphological, Immunohistochemical, Ultrastructural, and Cytogenetic Study of a Case and Review of the Literature

Poorly differentiated neuroendocrine carcinomas (PDNECs) of the kidney are extremely rare high-grade cancers accounting for only 42 cases reported in the literature. In this paper, we describe the morphological, immunohistochemical, ultrastructural, and for the first time, cytogenetic features of a renal PDNEC. In addition, we have reviewed the literature and compared the published clinicopathological data with our morphological and genetic results. The tumor arose within the kidney parenchyma and showed the typical histological features of a pure small cell PDNEC. Fluorescence in situ hybridization study demonstrated a complex chromosomal assessment indicative of a high degree of chromosome instability with gain of multiple chromosomes, loss of p53, and amplification of myc gene. These results suggest that renal PDNEC has a different genetic background to renal clear cell carcinoma, mainly characterized by the loss of the short arm of chromosome 3. Conversely, genetic alterations seem to resemble those of type 2 papillary renal cell carcinoma. The review of the literature demonstrated that PDNECs are associated with poor prognosis and that parenchymal tumors show some differences from those arising in the pelvis, in that parenchymal tumors are purely neuroendocrine while pelvic tumors are mostly mixed neuroendocrine–exocrine neoplasms.     

Recurrent Intrapulmonary Malignant Small Cell Tumor of the Thoracopulmonary Region with Metastasis to the Oral Cavity: Review of Literature and Case Report

Malignant small cell tumor of the thoracopulmonary region (MSCT) was first described in 1979 and has been referred to as the Askin tumor. This malignant neoplasm is a member of the peripheral primitive neuroectodermal tumor (PPNET) family and typically involves the periosteum, soft tissue, and extrapulmonary tissue of the thoracic wall. MSCT may also involve the lung parenchyma by local extension or may arise de novo in peripheral lung tissue. Local recurrence, abdominal involvement by tumor extravasation across the diaphragm, and skeletal metastatic disease are relatively common. However, metastasis to the head and neck region and in particular to the oral cavity is extremely rare. We present a recurrent intrapulmonary MSCT with metastasis to the oral cavity in an adolescent Hispanic boy, and review the literature regarding this member of the PPNET family. Differentiation from neuro-blastoma may be made based on immunoreactivity for β₂ microglobulin and HBA71 and lack of immunoreactivity for chromogranin in PPNET and MSCT. Ultrastructural features commonly seen in MSCT and PPNET are round to ovoid tumor cells with occasional cytoplasmic processes with relatively few pleomorphic dense core granules. These tumors lack the gangliocytic and Schwann cell differentiation that is characteristic of neuroblastoma. MSCT and PPNET have a common reciprocal cytogenetic translocation [t(11;22)q(24;q12)], which is shared with Ewing's sarcoma. Prognosis in MSCT is quite dismal, with a 2-year survival of 38% and a 6-year survival of only 14%.