Primary alveolar soft part sarcoma of uterine corpus: a case report with immunohistochemical, ultrastructural study and review of literature.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare mesenchymal malignancy. ASPS usually occurs most commonly in the deep soft tissues of the thigh and buttock or the head and neck regions. ASPS that originate from the uterine corpus are even more rare, with only 10 previous cases reported in the English literature. CASE PRESENTATION: In our case, the alveolar features were completely lost and the tumour shows a solid, non-alveolar pattern and the nuclei have marked variation in nuclear size, and multinucleation. The correct pathological diagnosis has been made by immuno- histochemical and ultrastructural features, which rvealed overexpression of TFE3 and peculiar cytoplasmic crystalline inclusions. In this paper, an additional case of primary ASPS of uterine corpus is reported with immunohistochemical, ultrastructural study and review of literature in the effort to delineate its clinical and pathological features. In this unusual site, the diagnosis can be problematic because ASPS can mimic other primary or metastatic uterine neoplasms. CONCLUSIONS: Thus, in this unusual presentation an essential diagnostic marker is the nuclear over-expression of TFE3 as well as ultrastructural study, which reveals the presence of peculiar cytoplasmic crystalline inclusions.

Brain metastasis of crystal-deficient, CD68-positive alveolar soft part sarcoma: ultrastructural features and differential diagnosis.

We report a case of alveolar soft part sarcoma (ASPS) presenting as an isolated frontal lobe metastasis. The tumor demonstrated little or no immunoreactivity for a broad panel of antibodies yet strong, diffuse immunoreactivity with CD68. On electron microscopy, the characteristic rectangular to rhomboid crystalline inclusions of ASPS were not present. Electron-dense granules resembling peroxisomes were present, sometimes in association with elongated granular structures having a periodic, lattice-like arrangement. Metastatic ASPS was confirmed by demonstration of an ASPSCR1-TFE3 fusion and imaging studies that excluded metastatic Xp11.2 translocation renal cell carcinoma. The primary site was subsequently identified in the lower extremity.

Alveolar soft part sarcoma of the paranasal sinuses masquerading as a giant invasive pituitary adenoma.

Alveolar soft part sarcoma (ASPS) is a relatively rare tumor that mostly presents as a slow growing mass in the deep soft tissue of the extremities. A substantial number of cases in children occur in the head and neck region; however, in any age group, it is very rarely reported in the sinonasal region. We report a case of ASPS of the paranasal sinuses with sellar extension in a 25-year-old man that masqueraded as a giant invasive pituitary adenoma. This is only the fifth case of sinonasal ASPS in literature. The clinical and radiological diagnoses were misleading, but an extensive pathology workup including electron microscopy helped reach an accurate diagnosis in this unusual case.

Cytopathological diagnosis of alveolar soft part sarcoma, a rare soft tissue neoplasm.

OBJECTIVE: Alveolar soft part sarcoma (ASPS) is a rare soft tissue neoplasm, having various morphological mimics, especially on fine needle aspiration cytology (FNAC). Because no definite immunohistochemical markers are available to aid a correct diagnosis, knowledge of the cytomorphological features is essential for correct patient management. Cytological features of five cases of ASPS are discussed, along with the ultrastructural findings available in one of them. METHODS: Cytology records from 1997 to 2009 were reviewed for cases with a diagnosis of ASPS on cytology. The histology slides of the cases were also assessed for confirmation of the diagnosis. All the slides were reviewed by three pathologists. RESULTS: There were five cases of ASPS diagnosed on FNAC. Their cytological features were noted in detail. The diagnoses in all the cases were confirmed on histology, and ultrastructural findings available in one of them were also assessed. CONCLUSIONS: The knowledge of cytological features may aid in diagnosing this rare tumour correctly on FNA smears, thus enabling correct patient management.

Alveolar soft-part sarcoma: a review and update.

Alveolar soft-part sarcoma (ASPS) is a rare, distinctive sarcoma, typically occurring in young patients. Although it displays a relatively indolent clinical course, the ultimate prognosis is poor and is often characterised by late metastases. Recently, our understanding of the genetic events underlying the pathogenesis of ASPS has greatly increased. The historical, histopathological, ultrastructural, immunohistochemical and genetic aspects of ASPS are reviewed in this article.

Cytologic features of alveolar soft part sarcoma: report of three cases.

Alveolar soft part sarcoma (ASPS) is a rare, high-grade, epithelial-like sarcoma that shows characteristic histopathologic findings. Although a chromosomal anomaly that seems specific has been recently described, its diagnosis is based on histologic and ultrastructural features. The tumor shows no specific immunohistologic findings. Cytologic features of three cases of ASPS are presented. Preoperative fine-needle aspiration (FNA) of the primary soft tissue tumor was performed in two cases. In another two, mediastinal and pulmonary and subcutaneous metastatic lesions were aspirated. In all cases the cytologic image was identical with numerous, dissociated, large neoplastic cells with round-to-plasmocytoid morphology. Cytoplasmic fragility and granularity with abundant, atypical, naked nuclei were present. In one case, FNA material was available for ultrastructural studies. It disclosed the characteristic cytoplasmic crystalline structures. A specific cytologic diagnosis of ASPS was given in all cases. In conclusion, ASPS is a rare neoplastic entity that shows a characteristic cytologic image. When accompanied by an adequate clinical context it permits specific preoperative recognition. While immunocytologic studies are helpful to exclude other neoplasms, ultrastructure may result in an exact diagnosis.

Alveolar soft part sarcoma. Report of a case diagnosed by needle aspiration cytology and electron microscopy.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare tumor, accounting for less than 1% of all primary soft tissue malignant neoplasms. The tumor is a distinct clinicopathologic entity, but its histogenesis is controversial. CASE: The needle aspirate from a soft tissue tumor in a 15-year-old girl was stained with Diff-Quik and periodic acid--Schiff (PAS) with and without prior digestion with diastase. Minute tumor tissue fragments were processed for transmission electron microscopic examination (EM). Clustered malignant cells with ill-defined, frothy or vacuolated cytoplasm showed a positive reaction with PAS and PAS with prior diastase digestion and oval nuclei containing macronucleoli. Intracytoplasmic, membrane-bound, rhomboid and rod-shaped crystals with a regular lattice pattern with 50-80 A periodicity were detected by EM study of aspirated tumor cells. CONCLUSION: Light and EM studies of aspirated tumor cells showed diagnostic features of the tumor.

Crystals of alveolar soft part sarcoma in a fine needle aspiration biopsy cytology smear. A case report.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor. It has characteristic histomorphology, with typical ultrastructural features demonstrating unique crystalloids. It occurs predominantly in adolescents and young adults, in whom the most common location is within the fascial planes of skeletal muscle of the lower extremity. CASE: We present fine needle aspiration biopsy (FNAB) findings along with histopathologic features and ultrastructural appearance of a large gluteal mass in a 29-year-old female. FNAB cytology smears showed single and small groups of polyhedral malignant cells with granular cytoplasm, anisokaryosis and prominent nucleoli. The delicate cytoplasm had a tendency to rupture, with the presence of many bare nuclei. The characteristic crystals were observed in Papanicolaou-stained smears within the cytoplasm and in the background near the tumor cells. This consolidated the radiologic suspicion of ASPS and facilitated the application of relevant ancillary tests. Biopsy of the mass showed the characteristic histologic pattern. Electron microscopy confirmed the diagnosis with demonstration of membrane-bound, rhomboid crystalloids with a latticelike ultrastructure. CONCLUSION: Detection of characteristic crystalloids in Papanicolaou-stained FNAB smears facilitated a proper evaluation and correct diagnosis of ASPS.

Fine needle aspiration cytology and core biopsy in the diagnosis of alveolar soft part sarcoma presenting with lung metastases. A case report.

BACKGROUND: Alveolar soft part sarcoma is a rare soft tissue tumor of uncertain origin usually affecting young adults. This neoplasm has early metastatic potential. Its cytologic features, particularly when presenting with metastases, have rarely been described. CASE: A 23-year-old male presented with shortness of breath and scapular pain. Routine chest roentgenograms revealed multiple lung nodules. Malignancy was established by percutaneous fluoroscopically guided fine needle aspiration on a lung nodule. Possible metastatic alveolar soft part sarcoma was suggested by cytology among few considerations in the differential diagnosis. Alveolar soft part sarcoma was confirmed by lung core biopsy and further supported by immunohistochemistry and electron microscopy. Tumor cells expressed muscle-specific actin and myoglobin, and contained diastase-resistant inclusions with periodic acid-Schiff stain. Ultrastructurally, peculiar, elongated intracytoplasmic crystalline bodies typical of this neoplasm were identified. A meticulous clinical search led to finding the primary tumor deeply located in the right posterior thigh. CONCLUSION: Aspiration cytology is a reliable, cost-efficient technique in the diagnostic workup of masses suspicious for malignancy.

Diagnostic value of electron microscopy in rare malignant musculoskeletal tumors. Experience from an orthopedic tumor center.

Rare musculoskeletal tumors can be difficult to diagnose by light microscopy or immunohistochemistry. Electron microscopy can be of diagnostic assistance especially if histotype specific ultrastructural features exist. In particular, electron microscopy for uncommon sarcomas such as alveolar soft part sarcoma, parachordoma, atypical Ewing's sarcoma and epithelioid sarcoma may be the diagnostic modality of choice.

Alveolar soft part sarcoma of the larynx: a case report of an unusual location with immunohistochemical and ultrastructural analyses.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare mesenchymal neoplasm of uncertain origin. In this article, we report a case of ASPS occurring in the larynx, an extremely rare location for this rather unusual tumor. METHODS AND RESULTS: The patient was a 34-year-old Japanese woman who requested an examination for hoarseness. The tumor showed a proliferation of large polygonal cells with periodic-acid-Schiff-positive diastase-resistant intracytoplasmic granules, arranged in an alveolar growth pattern. The cytoplasm of the tumor cells was eosinophilic. Tumor cells were positive for vimentin and titin. Nuclear immunoreactivity for TFE3 was observed, and the Ki-67 labeling index was 14.7%. Ultrastructurally, electron-dense rod-shaped crystals were infrequently observed in the cytoplasm. This case was finally diagnosed as ASPS of the larynx. CONCLUSION: We discuss the histogenesis and differential diagnosis of ASPS with immunohistochemical and ultrastructural findings. TFE3 immunohistochemistry was found to be a very useful marker for the diagnosis of ASPS.

Alveolar soft part sarcoma.

This article provides an overview of the pathology of alveolar soft part sarcoma, focused on its morphology, special stains useful in diagnosis, and the clinical and radiographic features of the disease. Alveolar soft part sarcoma is a rare neoplasm of unknown histogenesis with poor prognosis. Although there are several immunohistochemical stains available to help reach the diagnosis, the morphology of the tumor should be considered the main diagnostic feature. The periodic acid-Schiff stain is the best single stain that supports the diagnosis.

Crystal-deficient alveolar soft part sarcoma.

Classically, ultrastructural examination of alveolar soft part sarcoma reveals large, dramatic, rhomboid to needlelike crystals with a characteristic substructure. In this study of four cases of alveolar soft part sarcoma, only two exhibited large crystals, which were rare. All four cases, however, exhibited round, electron-dense granules, and in the two cases without large crystals these granules rarely exhibited elongation with the characteristic substructure of alveolar soft part sarcoma that permits definitive diagnosis. Two of these cases had been previously studied at other institutions, where crystals were not identified ultrastructurally and electron microscopy was considered noncontributory. Large crystals, then, may be rare or absent in alveolar soft part sarcoma. Careful search may be necessary to find granules with the characteristic periodic substructure.

Smooth tubular aggregates associated with plasmalemmal invagination in alveolar soft part sarcoma.

The ultrastructure of four alveolar soft part sarcomas was examined to search for ultrastructural signs of myogenic or neural origin. A new ultrastructural structure, an unusual tubular structure, was found in two of four cases. The structure appeared as a large, smooth, tubular aggregate in the cytoplasm of some tumor cells but did not show a honeycomb arrangement of tubules. The aggregate was composed of long, serpentine, branching, smooth, irregularly arranged tubules without ribosomes that ran in various directions. The aggregates intermingled with small amounts of cytoplasmic organelles. Because the aggregated tubules were at times continuous with cell membranes, it was shown that they were the complex extensions or invaginations of cell membranes. Neither myelin-axon complexes nor myofilaments, including Z band material, were seen in any case. There was a possibility that the smooth tubular aggregate was a T-tubule-like structure, suggesting that the tumors were derived from skeletal muscle cells.

Ultrastructural studies of tubules, analogous to skeletal cell T-tubules, in alveolar soft part sarcoma.

Tumor tissues from six patients with alveolar soft part sarcoma (ASPS) were investigated ultrastructurally to determine the presence of smooth tubules associated with plasmalemmal invaginations. Two different types of smooth tubular structures were identified: an aggregated and a dispersed type. The aggregated type (found in one of the six ASPSs) showed marked aggregation of many elongated smooth tubules without ribosomes associated with the plasmalemma. In the dispersed type (observed in the remaining five ASPSs), there was a conspicious appearance of a few smooth tubules scattered throughout the cytoplasm. Smooth tubules were the main component in both types, suggesting that both types appeared to have the same origin, although there were some differences in number, appearance, and distribution of the tubules between the two types. The smooth tubules in both types were classified into three different subtypes on the basis of materials in the tubular lumen. Ultrastructual observation and a plasmalemmal tracer-method, showed smooth tubules in continuity with the plasmalemma in three of the six cases, indicating that the tubules originated from the plasmalemma. Since the tubular structures were found in the tumor tissues of all six patients, they are probably one of the characteristic features of ASPS.

Alveolar soft-part sarcoma: further evidence by FISH for the involvement of chromosome band 17q25.

A cytogenetic study of an alveolar soft-part sarcoma, a rare tumor of probably myogenic origin, demonstrated a t(X;17)(p11;q25) as the sole chromosomal abnormality. Dual- and triple-color fluorescence in situ hybridization, performed on metaphase and interphase cells, confirmed the translocation between chromosomes X and 17 and demonstrated that this translocation resulted in loss of 17q25. Involvement of 17q25 has been described in four previously published cases of alveolar soft-part sarcoma, but without further characterization. Compared to our karyotype, it seems that the derivative chromosome 17 observed in the reported cases could also be the result of a t(X;17) with possible loss of the 17q25 band. If so, a 17q25 deletion and/or chromosome rearrangement between Xp and 17q leading either to a gene fusion or gene disruption could play an important role in the pathogenesis of alveolar soft-part sarcoma.

[Alveolar sarcomas of soft tissues. Immunohistochemical, ultrastructural study and flow cytometry]. / Les sarcomes alveolaires des parties molles etude immunohistochimique, ultrastructurale et cytometrie en flux.

Alveolar soft tissue sarcoma is an unusual tumor, known to have a poor prognosis. Although a muscular origin has been supported by most authors, the histogenesis of such tumors remains unclear. We report a case of alveolar soft tissue sarcoma with histological, ultrastructural, immunohistochemical and flow cytometry study. Pour results support a myogenic origin of these tumors and demonstrate its aneuploid nature. Pulmonary metastasis occurred early in spite of intensive chemotherapy and surgical removal of the tumor.