Histopathological characterization of aortic intimal sarcoma with multiple tumor emboli

A case of aortic intimal sarcoma with multiple tumor emboli and distal metastasis is reported. All metastasis (adrenal, spleen) were via the arteries. This case also had independent lung cancer. Macroscopically, the aortic tumor did not form a bulged mass, but had linear ulceration with abundant mural thrombi. Poorly cohesive large atypical cells were seen in the intima of the abdominal aorta without invasion into the media. Tumor cells were disseminated into the mural thrombi on the aorta and embolized its branches. In the metastatic tumor or tumor emboli of the distal artery, there were not only large atypical cells, but also the foci of spindle-shaped cells or epithelioid differentiation. Tumor cells in the aorta were immunohistochemically positive for only vimentin. Muscle-specific actin was positive focally for spindle-shaped cells of tumor emboli and metastatic tumors. Furthermore, cytokeratin-positive cells were scatteredly seen. All tumor cells were negative for factor VIII and did not have a histologic or phenotypic analogy with lung cancer. The primary intimal sarcoma in the present case was of undifferentiated non-endothelial intimal stromal cell origin, and may have had multipotential for differentiation. Investigation of the metastatic site was useful for recognizing the features of this tumor.     

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.     

Alveolar soft part sarcoma of the uterine cervix

A rare case of an alveolar soft part sarcoma of the uterine cervix in an 8 year old girl is presented. The patient was admitted because of genital bleeding lasting for 7 months. A polypoid tumor, 2times1.5 cm in diameter, was found in her external uterine os and was surgically resected. Microscopically, the tumor consisted of a uniform sheet of tumor cells in the cytoplasm which contained granules and which were stained with periodic acid-Schiff, both before and after the diastase digestion. Alveolar arrangement of the tumor cells was manifested with reticulin silver impregnation. Dense, membrane bound granules were evident at an ultrastructural level in the cytoplasm of the tumor cells. An immunohistochemical examination demonstrated a positive reaction for anti-desmin, anti-myoglobin, anti-HHF35 and anti-neuron specific enolase in the cytoplasm.     

Spindle-cell non-pleomorphic atypical fibroxanthoma: analysis of a series and delineation of a distinctive variant

Atypical fibroxanthoma is a bizarre, cytologically malignant but usually clinically benign, lesion which typically arises in sun-damaged skin of the head and neck region in the elderly. Classically, its morphology is said to represent the dermal counterpart of pleomorphic malignant fibrous histiocytoma. We have identified 10 cases of a more monomorphic spindle-celled, fascicular variant which, paradoxically, was often mistaken for a clinically malignant lesion because it lacked the pleomorphism of conventional atypical fibroxanthoma. These tumours all arose in the head and neck region as polypoid lesions in the elderly. The tumours were confined to the dermis, often had an epidermal collarette, showed an eosinophilic fascicular morphology and were highly mitotic. All 10 were vimentin positive and five showed very focal actin positivity. Desmin, keratin and S-100 protein were negative in all cases. The clinical course was benign in all cases, justifying their accurate recognition. The principal differential diagnoses are spindle cell squamous carcinoma, spindle cell melanoma and leiomyosarcoma. Immunohistochemistry plays a key role in this distinction.     

Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases

Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, lysozyme (LYS)), Langerhans cells (CD1a), follicular dendritic cells (FDC: CD21, CD35) and S100 protein. This analysis revealed that 57 cases (93%) fit into four major immunophenotypic groups (one histiocytic and three dendritic cell types) utilizing six markers: CD68, LYS, CD1a, S100, CD21, and CD35. The four (7%) unclassified cases were further classifiable into the above four groups using additional morphological and ultrastructural features. The four groups then included: (i) histiocytic sarcoma (n=18) with the following phenotype: CD68 (100%), LYS (94%), CD1a (0%), S100 (33%), CD21/35 (0%). The median age was 46 years. Presentation was predominantly extranodal (72%) with high mortality (58% dead of disease (DOD)). Three had systemic involvement consistent with 'malignant histiocytosis'; (ii) Langerhans cell tumour (LCT) (n=26) which expressed: CD68 (96%), LYS (42%), CD1a (100%), S100 (100%), CD21/35 (0%). There were two morphological variants: cytologically typical (n=17) designated LCT; and cytologically malignant (n=9) designated Langerhans cell sarcoma (LCS). The LCS were often not easily recognized morphologically as LC-derived, but were diagnosed based on CD1a staining. LCT and LCS differed in median age (33 versus 41 years), male:female ratio (3.7:1 versus 1:2), and death rate (31% versus 50% DOD). Four LCT patients had systemic involvement typical of Letterer-Siwe disease; (iii) follicular dendritic cell tumour/sarcoma (FDCT) (n=13) which expressed: CD68 (54%), LYS (8%), CD1a (0%), S100 (16%), FDC markers CD21/35 (100%), EMA (40%). These patients were adults (median age 65 years) with predominantly localized nodal disease (75%) and low mortality (9% DOD); (iv) interdigitating dendritic cell tumour/sarcoma (IDCT) (n=4) which expressed: CD68 (50%), LYS (25%), CD1a (0%), S100 (100%), CD21/35 (0%). The patients were adults (median 71 years) with localized nodal disease (75%) without mortality (0% DOD). In conclusion, definitive immunophenotypic classification of histiocytic and accessory cell neoplasms into four categories was possible in 93% of the cases using six antigens detected in paraffin-embedded sections. Exceptional cases (7%) were resolvable when added morphological and ultrastructural features were considered. We propose a classification combining immunophenotype and morphology with five categories, including Langerhans cell sarcoma. This simplified scheme is practical for everyday diagnostic use and should provide a framework for additional investigation of these unusual neoplasms.     

Differentiating Small Round Cell Sarcomas of the Soft Parts by an Innovative Immunogold Labeling Method: An Ultrastructural Study

A new immunoelectron microscopy procedure was developed by remaking the fixed-frozen tissue specimens into LR White resin blocks suitable for postembedding colloidal gold immunolabeling, and used to examine 16 cases of small round cell soft tissue sarcomas. In rhabdomyosarcoma, ultrastructural double-immunogold staining demonstrated a coexpression of muscle specific actin and desmin in the same tumor cell. In both Ewing's sarcoma and peripheral neuroepithelioma, the heterogeneous expression of MIC2 gene product (p30/32^MIC2) in each tumor cell was demonstrated as well. In peripheral neuroepithelioma, the colloidal gold immunolabeling for neurofilament demonstrated the intermediate filaments surrounding microtubules. The procedure for ultrastructural colloidal gold immunolabeling using fixed-frozen tissue is thus considered to be useful not only for tumor diagnosis, but also for investigating various subcellular structures.     

Diagnosis of Ewing's sarcoma and related tumours by detection of chromosome 22q12 translocations using fluorescence in situ hybridization on tumour touch imprints

It is increasingly recognized that the identification of t(11;22)(q24;q12) is a useful aid in the accurate diagnosis of Ewing's sarcoma and related tumours. However, cytogenetic studies have a low success rate and adequate tumour is not always available. This study describes the use of fluorescence in situ hybridization (FISH) to detect translocations at 22q12, the site of the EWS gene involved in t(11;22)(q24;q12), on tumour touch imprints made from true cut core-needle biopsy and frozen tumour. Of the seven tumours analysed, five diagnosed as Ewing's sarcoma or primitive neuroectodermal tumour demonstrated chromosome translocation at 22q12. This is a rapid and reliable method to detect a diagnostically relevant chromosome translocation using minimal amounts of fresh or frozen tumour.     

Immunohistochemical analysis of Smac/DIABLO expression in human carcinomas and sarcomas

Second mitochondria-derived activator of caspases (Smac/DIABLO) is released from mitochondria into the cytosol during apoptosis, promoting caspase activation by neutralizing the inhibition of inhibitor of apoptosis proteins (IAPs) on caspases. Alteration of apoptosis is essential for cancer development, and cancer cell death by radiation and chemotherapy is largely dependent upon apoptosis. In this study, archival tissues of 100 carcinomas and 50 sarcomas from various origins were analyzed by immunohistochemistry for the expression of Smac/DIABLO. Smac/DIABLO immunoreactivity was seen in 62 of 100 (62%) carcinomas, including 42 of 60 stomach carcinomas, 7 of 10 colorectal carcinomas, 4 of 10 lung carcinomas, 7 of 10 ovarian carcinomas, and 2 of 10 prostate carcinomas. Smac/DIABLO is expressed in 11 of 50 (22%) sarcomas, including 2 of 8 malignant schwannomas, 5 of 11 rhabdomyosarcomas, 2 of 7 malignant fibrous histiocytomas, 1 of 6 leiomyosarcomas, 0 of 8 angiosarcomas, 0 of 8 liposarcomas, and 1 of 2 Ewing's sarcomas. These data demonstrated that Smac/DIABLO expression levels vary depending on the individual cancer types. Furthermore, the present study showed that many human cancers do not express Smac/DIABLO, and suggest that lack of Smac/DIABLO expression in the cancer cells may inhibit apoptosis, thereby promoting their survival.