Cytology of a parietal swelling in a 52-year-old man

Primary FNA diagnosis of brown tumour is challenging because overlapping of cytomorphologic features with other giant cell lesions. Clinical information, imaging and laboratory tests benefits the correct diagnosis.

Pitfalls in soft tissue cytopathology

Fine needle aspiration biopsy (FNAB) is a diagnostic modality for the evaluation of suspicious soft tissue masses. Despite its reasonable sensitivity, specificity and positive predictive value in differentiating benign from malignant neoplasms, the exact subtyping of the primary soft tissue tumours can be challenging. Certain tumours constitute "pitfalls" and add to the diagnostic challenge. This review provides a detailed account of the diagnostic challenges in soft tissue cytopathology, including pitfalls and, more importantly, the ways to overcome these challenges by integrating clinical details, key cytomorphological features and judicious application of ancillary techniques.

Interventional and EBUS cytology in Sweden

Interventional cytology was first introduced in Sweden in the late 1940ies by Sixten Franzén at the Karolinska University Hospital in Solna, Stockholm. In the early 1950ies, Nils Söderström started using the technique at the University Hospital in Lund. Cytology was successively established as common practice at the pathology departments in Sweden, and e.g. Solna and Lund today have a high rate of cytological samples. Over the years new techniques, such as endobronchial ultrasound (EBUS)-guided fine-needle aspirations, and analyses have been introduced, contributing to the maintained value of cytology as a diagnostic method. In this article, we present a brief history and the current situation of cytology in Sweden with focus on interventional and EBUS cytology.

The Small Round Cell Sarcomas Complexities and Desmoplastic Presentation

Background

Small round cell sarcomas (SRCSs) account for most solid malignancies in the pediatric age group and are a part of group of malignant tumors characterized by heterogenous clinical presentation and overlapping microscopic features of small, round, primitive cells. In addition to the recently established certain genetically defined subset of undifferentiated round cell sarcomas of soft tissue and bone, this group of sarcomas include desmoplastic small round cell tumor, poorly differentiated synovial sarcoma, alveolar rhabdomyosarcoma, mesenchymal chondrosarcoma, and small cell osteosarcoma. Although, those entities share clinical and cytomorphologic features and cannot be unequivocally classified based on clinical presentation and morphology alone. Most of SRCSs characterizes of particular patterns of protein expression or genetic changes and ancillary tests remain necessary to confirm or rule out a specific diagnosis. Subtle but occasionally distinctive cytologic features narrows the number of differential diagnoses and helps to select appropriate ancillary tests necessary for the final diagnosis. Thus, when adequate fine needle aspiration (FNA) biopsy specimen is combined with ancillary tests, a specific histologic diagnosis can be made in almost all cases. However, due to complex cytologic features of SRCS as well as various quality and diversity of FNA smears, there are cases in that cytologic features which do not entirely match the known diagnostic criteria.

Summary

The aim of this review was to summarize cytomorphologic criteria and to present rare and divergent cytological features of SRCSs. Careful assessment of clinical presentation, cytological features, immunohistochemical patterns, and molecular alternations is necessary for an accurate diagnosis. Knowing of rare and divergent microscopic findings that does not fit with the known cytological criteria will help to avoid misdiagnosis.

Key Messages

The role of FNA biopsies diagnosing soft tissue and bone tumors has been increasing because of the ability of ancillary tests to assist in the diagnosis of specific tumors. SRCSs may be diagnosed accurately in cytology specimens. Access to clinical and radiographic presentation, utility of ancillary tests, understanding complexity of cytological features, and awareness of the rare cytologic findings that differ from that of the established diagnostic criteria are essential to make correct diagnosis.

Comparative cytological and histological assessment of 828 primary soft tissue and bone lesions, and proposal for a system for reporting soft tissue cytopathology

Introduction

The aim of the study was to evaluate the diagnostic utility of fine needle aspiration (FNA) cytology and core needle biopsies (CNBs) in a series of primary soft tissue and bone lesions and to test a possible system for reporting results of FNA cytology of soft tissue lesion.

Methods

This retrospective study encompassed 828 primary soft tissue and bone lesions, analysed with FNA, CNB and/or surgical specimen in order to perform sensitivity/specificity as well as accuracy analyses. The series was then used to test a system for reporting soft tissue cytopathology with six categories and the risk of malignancy in each category was calculated.

Results

With a malignant diagnosis defined as positive test result, FNA and CNB analysis showed sensitivity of 87% and 94%, respectively, and specificity of 89% and 95%, respectively. FNA and CNB analyses identified the correct histopathological entity of the examined lesion in 55% and 66%, respectively. The risk of malignancy within the tested categories was non‐diagnostic 42%, non‐neoplastic 0%, atypia of unknown significance 46%, neoplasm benign 3%, neoplasm of unknown malignant potential 27%, suspicious for malignancy 72% and malignant 97%.

Conclusion

FNA cytology is a suitable tool to determine the malignant potential of a sampled soft tissue/bone lesion but is inferior to CNB in defining the correct entity. A standardised reporting system might improve the clinical management of patients with soft tissue tumours examined primarily by FNA cytology.

The study evaluated the diagnostic utility of fine needle aspiration cytology and core needle biopsies in 828 primary soft tissue and bone lesions. In a second step, a possible system for reporting results of fine needle aspiration cytology of soft tissue lesion was tested.

Role of fine needle aspiration cytology in the diagnosis of soft tissue tumours

Fine needle aspiration cytology (FNAC) is a widely accepted safe, simple and rapid diagnostic procedure used in the examination of neoplastic and non-neoplastic lesions of various locations. Since its introduction, FNAC has developed into an effective diagnostic tool practiced in a large majority of medical centres evaluating and treating oncological patients. The role of FNAC has been limited in the examination of primary soft tissue lesions, however, as many physicians working in this area recommended against using FNAC. An increasing use of minimally invasive diagnostic procedures in the last decade has resulted in a better acceptance of FNAC as a first-line approach or as a complementary tool to core needle biopsy in the diagnosis of musculoskeletal lesions. This review discusses the role and value of FNAC in the evaluation and treatment of soft tissue tumours based on the experience gathered over the course of 48 years at the Sarcoma Center in Lund, Sweden. FNAC reports most often provide diagnostic information allowing the initiation of treatment or, when definitive diagnosis cannot be rendered from a cytological examination, guiding the continued diagnostic investigation. The main advantages of soft tissue FNAC are good sensitivity and specificity, low morbidity, speed of diagnosis, and low cost/benefit ratio. The most important disadvantages stem from limited experience in cytological diagnosis of soft tissue tumours and a lack of standardised and uniform reporting system for soft tissue FNAC.

RNA sequencing of sarcomas with simple karyotypes: identification and enrichment of fusion transcripts

Gene fusions are neoplasia-associated mutations arising from structural chromosomal rearrangements. They have a strong impact on tumor development and constitute important diagnostic markers. Malignant soft tissue tumors (sarcomas) constitute a heterogeneous group of neoplasms with >50 distinct subtypes, each of which is rare. In addition, there is considerable morphologic overlap between sarcomas and benign lesions. Several subtypes display distinct gene fusions, serving as excellent biomarkers. The development of methods for deep sequencing of the complete transcriptome (RNA-Seq) has substantially improved the possibilities for detecting gene fusions. With the aim of identifying new gene fusions of biological and clinical relevance, eight sarcomas with simple karyotypes, ie, only one or a few structural rearrangements, were subjected to massively parallel paired-end sequencing of mRNA. Three different algorithms were used to identify fusion transcripts from RNA-Seq data. Three novel (KIAA2026-NUDT11, CCBL1-ARL1, and AFF3-PHF1) and two previously known fusions (FUS-CREB3L2 and HAS2-PLAG1) were found and could be verified by other methods. These findings show that RNA-Seq is a powerful tool for detecting gene fusions in sarcomas but also suggest that it is advisable to use more than one algorithm to analyze the output data as only two of the confirmed fusions were reported by more than one of the gene fusion detection software programs. For all of the confirmed gene fusions, at least one of the genes mapped to a chromosome band implicated by the karyotype, suggesting that sarcomas with simple karyotypes constitute an excellent resource for identifying novel gene fusions.

Hyaline matrix in hyalinizing trabecular tumor: Findings in fine-needle aspiration smears

Hyalinizing trabecular tumor (HTT) is a rare neoplasm which usually follows an indolent clinical course. The cytologic diagnosis of HTT can be challenging as these neoplasms share cytomorphological features with other thyroid neoplasms and paraganglioma. In fine-needle aspiration (FNA) smears a diagnosis of papillary thyroid carcinoma (PTC) or suspicion of PTC is often made. Herein we report cytologic findings in two patients with HTT examined by FNA. The key to a correct diagnosis is the recognition of a hyaline and colloid/amyloid-like material in the background of the smears. Immunocytochemical examination showing aberrant membranous and peripheral cytoplasmic staining for MIB-1 can help in rendering a correct diagnosis.

Fusions involving protein kinase C and membrane-associated proteins in benign fibrous histiocytoma

Benign fibrous histiocytoma (BFH) is a mesenchymal tumor that most often occurs in the skin (so-called dermatofibroma), but may also appear in soft tissues (so-called deep BFH) and in the skeleton (so-called non-ossifying fibroma). The origin of BFH is unknown, and it has been questioned whether it is a true neoplasm. Chromosome banding, fluorescence in situ hybridization, single nucleotide polymorphism arrays, RNA sequencing, RT-PCR and quantitative real-time PCR were used to search for recurrent somatic mutations in a series of BFH. BFHs were found to harbor recurrent fusions of genes encoding membrane-associated proteins (podoplanin, CD63 and LAMTOR1) with genes encoding protein kinase C (PKC) isoforms PRKCB and PRKCD. PKCs are serine-threonine kinases that through their many phosphorylation targets are implicated in a variety of cellular processes, as well as tumor development. When inactive, the amino-terminal, regulatory domain of PKCs suppresses the activity of their catalytic domain. Upon activation, which requires several steps, they typically translocate to cell membranes, where they interact with different signaling pathways. The detected PDPN-PRKCB, CD63-PRKCD and LAMTOR1-PRKCD gene fusions are all predicted to result in chimeric proteins consisting of the membrane-binding part of PDPN, CD63 or LAMTOR1 and the entire catalytic domain of the PKC. This novel pathogenetic mechanism should result in constitutive kinase activity at an ectopic location. The results show that BFH indeed is a true neoplasm, and that distorted PKC activity is essential for tumorigenesis. The findings also provide means to differentiate BFH from other skin and soft tissue tumors. This article is part of a Directed Issue entitled: Rare cancers.

A novel SERPINE1-FOSB fusion gene results in transcriptional up-regulation of FOSB in pseudomyogenic haemangioendothelioma

Pseudomyogenic haemangioendothelioma (PHE) is an intermediate malignant vascular soft tissue tumour primarily affecting children and young adults. The molecular basis of this neoplasm is unknown. We here used chromosome banding analysis, fluorescence in situ hybridization (FISH), mRNA sequencing, RT-PCR and quantitative real-time PCR on a series of morphologically well-characterized PHEs to show that a balanced translocation, t(7;19)(q22;q13), detected as the sole cytogenetic aberration in two cases, results in fusion of the SERPINE1 and FOSB genes. This translocation has not been observed in any other bone or soft tissue tumour. Interphase FISH on sections from eight additional PHEs identified the same SERPINE1-FOSB fusion in all cases. The role of SERPINE1, which is highly expressed in vascular cells, in this gene fusion is probably to provide a strong promoter for FOSB, which was found to be expressed at higher levels in PHEs than in other soft tissue tumours. FOSB encodes a transcription factor belonging to the FOS family of proteins, which, together with members of the JUN family of transcription factors, are major components of the activating protein 1 (AP-1) complex. Further studies are needed to understand the cellular impact of the aberrant expression of the FOSB gene, but as the t(7;19) resulting in the SERPINE1-FOSB fusion seems to be pathognomonic for PHE, FISH or RT-PCR could be useful for differential diagnostic purposes.

Cytogenetic and single nucleotide polymorphism array findings in soft tissue tumors in infants

Soft tissue tumors in children under one year of age (infants) are rare. The etiology is usually unknown, with external factors or congenital birth defects and hereditary syndromes being recognized in only a small proportion of the cases. We ascertained the cytogenetic findings in 16 infants from whom tumor tissue had been obtained during a 25-year period. In eight of them, single nucleotide polymorphism (SNP) array analyses could also be performed. No constitutional chromosome aberrations were detected, and assessment of clinical files did not reveal any congenital or later anatomical defects. Three tumors--one infantile fibrosarcoma, one embryonal rhabdomyosarcoma, and one angiomatoid fibrous histiocytoma (AFH)--had abnormal karyotypes. As the AFH had an exchange between chromosome arms 12p and 15q, additional fluorescence in situ hybridization and reverse transcription-polymerase chain reaction analyses were performed, unexpectedly revealing an ETV6/NTRK3 fusion. Three of the eight tumors, including the AFH with an abnormal karyotype, analyzed by SNP array showed aberrations (loss of heterozygosity or imbalances). The present series suggests that the addition of array-based technologies is valuable for detecting underlying pathogenetic mechanisms.

Elastic fibers in elastofibroma dorsi by fine-needle aspiration

Fine-needle aspiration (FNA) features of elastofibroma dorsi (EFD) in a 56-year-old woman were evaluated. The patient presented with 5 cm soft tissue mass located between the inferior part of scapula and the chest wall. FNA smears were hypercellular, characterized by a mixture of uniform spindle cells, mature adipocytes, and collagen tissue fragments in varying proportions. The cytological findings included abundant degenerated elastic fibers presented as linear ("braid-like") and globular bodies with shell-like and stellate appearances with serrate borders, permitting a diagnosis of EFD. Occurrence of degenerated elastic fibers in FNA smears of elastofibroma is a highly diagnostic sign in the typical clinical setting and eliminates the need for preoperative histological examination.

Comparison of the oestrogen and progesterone receptor status in primary breast carcinomas as evaluated by immunohistochemistry and immunocytochemistry: a consecutive series of 267 patients

OBJECTIVE

The use of cytological specimens to evaluate tumour biomarkers in metastatic breast cancer lesions has attracted increased interest because of the considerable number of reports that have shown discordance between the primary tumour and metastatic lesion. Oestrogen receptor (ER) and progesterone receptor (PgR) assays are crucial for the management of patients with breast cancer, in both adjuvant and palliative settings. The aim of this study was to compare the ER and PgR immunocytochemical analysis of fine needle aspiration (FNA) samples with the immunohistochemistry (IHC) of surgical specimens and core biopsies from primary breast cancers.

METHODS

The FNA specimens were prepared as cell blocks (n = 25) or ThinPreps (n = 258) for the immunocytochemistry (IC) ER and PgR analyses. Sixteen patients were excluded because of lack of follow-up (n = 1), neoadjuvant therapy (n = 3) or cell counts in their fine needle aspirates that were too low (n = 12). The results of IC on 25 cell blocks and 242 ThinPreps were compared with IHC on the corresponding core needle biopsies (n = 16) or excised tumours (n = 251). The ER and PgR status was defined as negative (when less than 10% of the nuclei were stained) or positive (when equal or more than 10% of the nuclei were stained). Kappa statistics were used to evaluate the concordance.

RESULTS

The ER concordance was 98% with ThinPrep (κ = 0.93) and 92% with cell block (κ = 0.82). The corresponding values for PgR were 96% (κ = 0.91) and 96% (κ = 0.92).

CONCLUSIONS

Our results confirm that, in cases in which biopsies or surgical specimens are not available, IC (with either cell block or ThinPrep techniques) is a reliable method for the determination of the ER and PgR status performed under strict conditions using primary breast carcinomas, and is therefore potentially useful in metastatic settings.

Myofibroblastoma: a potential pitfall in core needle biopsy of breast lesions

Myofibroblastoma (MFB) is a benign neoplasm arising most frequently in the adult breast, but it may occur in any other tissue with the exception of the central nervous system. Adequate treatment of this neoplasm consists of local excision. MFB shows characteristic histological features and a clear immunohistochemical profile and usually does not cause any diagnostic difficulties [1-4]. A rare variant of MFB such as the epithelioid subtype with sclerotic stroma, however, can resemble lobular carcinoma in routinely stained histological sections.

Reclassification and subtyping of so-called malignant fibrous histiocytoma of bone: comparison with cytogenetic features

Background

The diagnostic entity malignant fibrous histiocytoma (MFH) of bone is, like its soft tissue counterpart, likely to be a misnomer, encompassing a variety of poorly differentiated sarcomas. When reviewing a series of 57 so-called MFH of bone within the framework of the EuroBoNeT consortium according to up-to-date criteria and ancillary immunohistochemistry, a fourth of all tumors were reclassified and subtyped.

Methods

In the present study, the cytogenetic data on 11 of these tumors (three myoepithelioma-like sarcomas, two leiomyosarcomas, one undifferentiated pleomorphic sarcoma with incomplete myogenic differentiation, two undifferentiated pleomorphic sarcomas, one osteosarcoma, one spindle cell sarcoma, and one unclassifiable biphasic sarcoma) are presented.

Results

All tumors were high-grade lesions and showed very complex karyotypes. Neither the overall pattern (ploidy level, degree of complexity) nor specific cytogenetic features distinguished any of the subtypes. The subgroup of myoepithelioma-like sarcomas was further investigated with regard to the status of the EWSR1 and FUS loci; however, no rearrangement was found. Nor was any particular aberration that could differentiate any of the subtypes from osteosarcomas detected.

Conclusions

chromosome banding analysis is unlikely to reveal potential genotype-phenotype correlations between morphologic subtypes among so-called MFH of bone.

Ezrin expression predicts local recurrence and development of metastases in soft tissue sarcomas

BACKGROUND

Ezrin is a cytoskeletal protein involved in tumour growth and invasion. Ezrin expression has been suggested to play a role in metastasis in paediatric osteosarcoma and rhabdomyosarcoma.

AIM

To evaluate the prognostic role of ezrin in a large series of soft tissue sarcoma of the extremities and trunk wall.

METHODS

Ezrin expression was evaluated by immunohistochemistry on tissue microarrays from a mixed series of 256 soft tissue sarcomas. The expression patterns were correlated to local recurrence and metastasis as well as to established prognostic factors in soft tissue sarcoma.

RESULTS

Increased ezrin expression predicted development of metastasis (HR=1.8, 95% CI 1.1 to 2.8; p=0.007) and local recurrence, also after adjustment for surgical margin (HR=2.4, 95% CI 1.4 to 4.3; p=0.02). Correlations to established prognostic factors showed strong associations between ezrin and necrosis (OR=3.9, p<0.0001) and ezrin and growth pattern (OR=3.1, p=0.03).

CONCLUSIONS

Ezrin independently predicts development of local recurrences and metastases in soft tissue sarcomas. The possibility of preoperative evaluation makes ezrin a potential marker for identification of high-risk sarcoma patients who would benefit from neoadjuvant therapy.

Expression levels of HMGA2 in adipocytic tumors correlate with morphologic and cytogenetic subgroups

Background

The HMGA2 gene encodes a protein that alters chromatin structure. Deregulation, typically through chromosomal rearrangements, of HMGA2 has an important role in the development of several mesenchymal neoplasms. These rearrangements result in the expression of a truncated protein lacking the acidic C-terminus, a fusion protein consisting of the AT-hook domains encoded by exons 1–3 and parts from another gene, or a full-length protein; loss of binding sites for regulatory microRNA molecules from the 3' untranslated region (UTR) of HMGA2 has been suggested to be a common denominator.

Methods

Seventy adipocytic tumors, representing different morphologic and cytogenetic subgroups, were analyzed by qRT-PCR to study the expression status of HMGA2; 18 of these tumors were further examined by PCR to search for mutations or deletions in the 3'UTR.

Results

Type (full-length or truncated) and level of expression varied with morphology and karyotype, with the highest levels in atypical lipomatous tumors and lipomas with rearrangements of 12q13-15 and the lowest in lipomas with 6p- or 13q-rearrangements, hibernomas, spindle cell lipomas and myxoid liposarcomas. All 18 examined tumors showed reduced or absent expression of the entire, or parts of, the 3'UTR, which was not due to mutations at the DNA level.

Conclusion

In adipocytic tumors with deregulated HMGA2 expression, the 3'UTR is consistently lost, either due to physical disruption of HMGA2 or a shift to production of shorter 3'UTR.

Identification of p53 as a strong predictor of survival for patients with malignant peripheral nerve sheath tumors

The purpose of this study was to identify new prognostic biomarkers with clinical impact in malignant peripheral nerve sheath tumor (MPNST), a highly aggressive malignancy for which no consensus therapy exists besides surgery. We have used tissue microarrays (TMAs) to assess in situ expression of 14 cell-cycle-regulating proteins in 64 well-characterized MPNST patients: 36 sporadic and 28 with neurofibromatosis type 1 (NF1). We developed a new software application for evaluation and logistics of the TMA images and performed a literature survey of cell cycle proteins in MPNST. For NF1-associated patients, there was a clear association between nuclear expression of p53 and poor survival (p = 0.004). Among the other proteins analyzed, we also found significant associations between survival and clinical variables, but none were as strong as that for p53. For the total series of MPNSTs, p53 was shown to be an independent predictor of survival, and patients without remission, with tumor size larger than 8 cm, and with positive p53 expression had a 60 times greater risk of dying within the first 5 years compared with the remaining patients (p = 0.000002). This is the most comprehensive study of in situ protein expression in MPNST so far, and expressed p53 was found to be a strong surrogate marker for outcome. Patients in complete remission with a primary p53-positive MPNST diagnosis may be considered in a high-risk subgroup and candidates for adjuvant treatment.

Deep-seated ordinary and atypical lipomas: histopathology, cytogenetics, clinical features, and outcome in 215 tumours of the extremity and trunk wall

Deep-seated lipomas are often atypical histologically and are considered by some to have a high risk of recurrence after excision. We reviewed 215 deep-seated lipomas of the extremities and trunk wall with reference to histology, cytogenetics, clinical features and local recurrence. We classified tumours with atypical features and/or ring chromosomes as atypical lipomas. These were more common in men, larger than ordinary lipomas and more often located in the upper leg. The annual incidence was estimated as ten per million inhabitants and the ratio of atypical to ordinary lipomas was 1:3. In total, six tumours (3%), recurred locally after a median of eight years (1 to 16); of these, four were classified as atypical. The low recurrence rate of deep-seated lipomas of the extremity or trunk wall, irrespective of histological subtype, implies that if surgery is indicated, the tumour may be shelled out, that atypical lipomas in these locations do not deserve the designation well-differentiated liposarcoma, and that routine review after surgery is not required.

Low-grade fibromyxoid sarcoma is difficult to diagnose by fine needle aspiration cytology: a cytomorphological study of eight cases

BACKGROUND

Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon neoplasm with bland morphology and an indolent clinical course, although metastases may develop in approximately 5-10% of the cases. The diagnosis of LGFMS can be difficult to render from fine needle aspiration cytology (FNAC) alone because of morphological overlap with other spindle cell and myxoid lesions.

OBJECTIVE

To determine cytological criteria for LGFMS by reviewing FNAC aspirates in eight cases and to compare the findings with those in subsequent histological sections.

METHODS

FNAC slides were reviewed from eight patients with subsequently excised tumours diagnosed as LGFMS. Of these patients, six also had core needle biopsies (CNB). Cytogenetic and/or molecular analysis was carried on all tumours.

RESULTS

The patients were six men and two women ranging in age from 26 to 78 years. Tumours arose in the deep soft tissues of the thigh (n = 5), shoulder girdle (n = 1) or upper arm (n = 1) and one in the subcutaneous tissue of the abdominal wall. Cytological features included clusters of bland spindle and round/polygonal cells embedded in a collagenous and myxoid matrix along with dissociated, uniform or slightly/moderately pleomorphic spindle cells, bare nuclei and fragments of collagen and myxoid tissue in varying proportions. Unequivocal sarcoma was diagnosed in two aspirates, but mitoses were absent in all cases. In three cases, the diagnosis was inconclusive with regard to benignity or malignancy, while three were erroneously diagnosed as benign spindle cell lesions. Although the diagnosis was suggested on three of six CNB, these presented similar diagnostic problems.

CONCLUSIONS

There were no cytomorphological findings in FNAC to allow for a clear cut separation of LGFMS from other spindle cell or myxoid lesions, but high-grade sarcoma could be excluded. Surgical (incisional or excisional) biopsy or, alternatively, examination of RT-PCR for the FUS/CREB3L or FUS/CREB3L1 fusion transcripts may be necessary to obtain a correct diagnosis.

Unstable translocation (8;22) in a case of giant cell reparative granuloma

Giant cell reparative granuloma (GCRG) is an uncommon lesion most often affecting the jaw but also the small bones of the hands and feet. GCRG overlaps clinically and radiographically with other giant cell-rich tumors such as giant cell tumor of bone (GCTB) and aneurysmal bone cyst (ABC). In the only case of a cytogenetically investigated GCRG reported previously, a balanced translocation involving chromosomes 4 and X was found. In the present study, chromosome banding and fluorescence in situ hybridization (FISH) analyses were used to characterize the primary lesion and local recurrence of a GCRG in the thumb and skin biopsy of a 45-year-old woman. The skin showed a normal karyotype. Various forms of a dic(8;22) containing 8q, 22q, and smaller or larger parts of 8p were found in both GCRG samples. In addition, ring chromosomes, most often composed of chromosome 11 material, and telomeric associations were found. The latter aberrations were more frequent in the primary lesion. Normal FISH signals were seen when using probes capable of detecting USP6 rearrangements. The variant 8;22 aberrations were interpreted to originate from an unstable dic(8;22)(p23;p11) that gradually evolved into a functionally monocentric chromosome in the dominating subset of cell populations. We conclude that our case of GCRG shared several cytogenetic characteristics with GCTB but none with ABC.

The complex cytological features of synovial sarcoma in fine needle aspirates, an analysis of four illustrative cases

OBJECTIVE

The cytological features of conventional monophasic spindle cell and biphasic synovial sarcoma have been defined in detail in several large series. The cytology of rare morphological variants, especially the subtypes of poorly differentiated synovial sarcoma, are insufficiently evaluated and diagnostically difficult to define. The objective of the present study was to call attention to the variable cytology of rare variants of synovial sarcoma. Furthermore, adjunctive diagnostic methods, necessary for a correct diagnosis, are discussed.

METHODS

Aspirates from four synovial sarcomas, with cytological features, which differed from those of conventional synovial sarcoma and from each other, were retrieved from our files and re-evaluated.

RESULTS

In three of the cases a correct diagnosis was not obtained from routinely stained aspirates. In the fourth case, the correct diagnosis was established by a combination of cytomorphology, immunocytochemistry and fluorescence in situ hybridization (FISH) performed on the aspirated material.

CONCLUSION

Ancillary diagnostic methods are necessary in the examination of aspiration smears from synovial sarcoma, especially of morphological variants with a cytomorphology that differs from conventional spindle-cell monophasic and biphasic tumours. Immunocytochemistry and molecular genetic examinations (reverse transcriptase polymerase chain reaction or FISH) are the methods of choice.

Assessment of the clinical and molecular impact of different cytogenetic subgroups in a series of 272 lipomas with abnormal karyotype

Conventional lipomas harbor karyotypic changes that could be subdivided into four, usually mutually exclusive, categories: rearrangement, in particular through translocations, of chromosome bands 12q13-15, resulting in deregulation of the HMGA2 gene, loss of material from or rearrangement of chromosome 13, supernumerary ring or giant marker chromosomes, and aberrations of chromosome band 6p21. In the present study, 272 conventional lipomas, two-thirds of them deep-seated, with acquired clonal chromosome changes were assessed with regard to karyotypic and clinical features. A nonrandom distribution of breakpoints and imbalances could be confirmed, with 83% of the cases harboring one or more of the previously known cytogenetic hallmarks. Correlation with clinical features revealed that lipomas with rings/giant markers were larger, occurred in older patients, were more often deep-seated, and seemed to have an increased tendency to recur locally, compared with tumors with other chromosome aberrations. The possible involvement of the HMGA2 gene in cases that did not show any of the characteristic cytogenetic changes was further evaluated by locus-specific metaphase fluorescence in situ hybridization (FISH) and RT-PCR, revealing infrequent cryptic disruption of the gene but abundant expression of full length or truncated transcripts. By FISH, we could also show that breakpoints in bands 10q22-23 do not affect the MYST4 gene, whereas breakpoints in 6p21 or 8q11-12 occasionally target the HMGA1 or PLAG1 genes, respectively, also in conventional lipomas.

Clinical course of nonvisceral soft tissue leiomyosarcoma in 225 patients from the Scandinavian Sarcoma Group

BACKGROUND

Leiomyosarcoma of nonvisceral soft tissues is an uncommon malignant tumor; thus, only small numbers of cases have been reported. This study was based on a large series of patients from the Scandinavian Sarcoma Group Register acquired during a 15-year period (from 1986 to 2001). Follow-up information was available for all patients.

METHODS

The authors analyzed the clinical features of 225 patients with cutaneous, subcutaneous, or deep-seated leiomyosarcoma of the extremities, trunk wall, and superficial parts of the head and neck region to determine the natural course of the disease. Only patients who received their treatment at a specialist sarcoma center were included. Re-evaluation of histopathology was performed.

RESULTS

The age of the patients (121 women and 104 men) ranged from 20 years to 98 years (median, 70 years), and the tumors ranged in size from 0.6 cm to 35 cm (median, 4.0 cm). Eighty-two percent of the tumors were classified as high grade. The median follow-up for survivors was 5.5 years. The local treatment was adequate in 154 of 206 patients (75%) who were without metastasis at presentation. At 10 years, 84% of the 206 patients with localized disease at presentation were free from local recurrence, 66% remained metastasis free, and 49% were alive. Multivariate analysis showed that higher malignancy grade (P = .006), larger tumor size (P = .003), and deeper tumor location (P = .002) were correlated significantly with decreased metastasis-free survival, inadequate local treatment was correlated with local recurrence (P = .007), and high malignancy grade was correlated with decreased overall survival (P = .007).

CONCLUSIONS

The long-term prognosis for patients with subcutaneous and deep-seated soft tissue leiomyosarcoma remains poor despite the ability to achieve adequate local control through nonmutilating surgery with or without radiotherapy.

Fine-needle aspiration of neurilemoma (schwannoma). A clinicocytopathologic study of 116 patients

The preoperative fine-needle aspiration cytology (FNAC) diagnoses in 116 surgically excised neurilemomas were reviewed and compared with the corresponding histopathologic diagnoses made on surgical specimens and with clinical data. In addition, the utility of adjunctive techniques was analyzed and other spindle-cell lesions in the differential diagnoses were discussed. An unequivocal, benign diagnosis was rendered by FNAC in 80 cases, 67 of which were correctly labelled as neurilemoma in a review of the original cytology reports. There were 6 false-positive malignant diagnoses while 23 smears were considered insufficient and 7 inconclusive as to whether benign or malignant. On reevaluation, the diagnostic smears in most cases contained spindle cells with wavy nuclei embedded in a fibrillar, occasionally collagenous, and/or myxoid matrix and Antoni A/Antoni B tissue fragments. A moderate to abundant admixture of round to oval cells was also frequent. Nuclear palisading was seen in 41 smears with distinctive Verocay bodies in 10. Markedly pleomorphic nuclei were seen in smears from 8 ancient and 6 conventional neurilemomas, and slight to moderate nuclear pleomorphism was observed in 38 additional cases. Thus most neurilemomas have distinct cytomorphologic features that allow correct diagnosis. The major problem in FNAC of neurilemoma is to obtain sufficient material. Furthermore aspirates showing predominantly Antoni A features, nuclear pleomorphism, and/or myxoid changes can easily be confused with other types of benign or malignant soft-tissue tumors.

Fusion of the SEC31L1 and ALK genes in an inflammatory myofibroblastic tumor

Inflammatory myofibroblastic tumor (IMT) is a neoplasm composed of myofibroblastic spindle cells and infiltrating inflammatory cells. Cytogenetic analyses have revealed that a subgroup of IMT, in particular among children and young adults, harbors clonal chromosomal rearrangements involving chromosome band 2p23. Further, molecular genetic studies have shown that these rearrangements target the ALK gene, serving as the 3'-partner in fusion genes with various translocation partners. In the present study, we describe the finding of a novel SEC31L1/ALK fusion gene in an intraabdominal IMT of a young man. G-band analysis revealed a translocation t(2;4)(p23;q21) and subsequent fluorescence in situ hybridization with locus-specific probes strongly indicated disruption of the ALK locus on chromosome 2. Immunostaining with monoclonal mouse anti-human CD246 ALK Protein showed diffuse cytoplasmic positivity. Using reverse primers for the ALK-gene, we could, by 5'-RACE methodology, amplify a single 1.2 kb fragment. Sequence analysis showed that the fragment was a hybrid cDNA product in which nt 3012 of SEC31L1 (NM_016211), located in band 4q21, was fused in-frame to nt 4080 of ALK (NM_004304). RT-PCR with two sets of primer pairs specific for SEC31L1 and ALK amplified two transcripts, which at sequencing corresponded to two types of chimeric SEC31L1/ALK transcripts. In the long, type I, transcript nt 3012 of SEC31L1 (NM_016211) was fused in-frame to nt 4080 of ALK. In the short, type II, transcript nt 2670 of SEC31L1 was fused in-frame to nt 4080 of ALK. Genomic PCR and subsequent sequencing showed that the breakpoints were located in intron 23 of SEC31L1 and intron 20 of ALK.

Fine-needle aspiration of soft tissue leiomyosarcoma: An analysis of the most common cytologic findings and the value of ancillary techniques

This study aims to determine the diagnostic accuracy of fine-needle aspiration cytology (FNAC) of primary leiomyosarcoma (LMS) of soft tissue and to review diagnostic criteria and adjunctive methods, which can contribute to a confident diagnosis. We evaluated the preoperative FNAC in 89 patients with primary LMS for the following: cytomorphology and correspondence of FNA to histological features of excised tumors and clinical data. In addition, the utility of adjunctive techniques was analyzed and other spindle-cell lesions in the differential diagnoses were discussed. An unequivocal, malignant diagnosis was rendered by FNAC in 78 cases; 74 tumors were diagnosed as sarcoma, of which 31 as LMS or suspicion of LMS. In addition, three smears were labeled as malignant tumor, one as carcinoma metastasis, and three as neurilemmoma. Seven aspirates were inconclusive and one insufficient. On reevaluation, the diagnostic smears in most cases contained tumor cell fascicles with an admixture of dispersed cells or stripped nuclei. The most common cells were spindle cells with elongated, blunt-ended, segmented or fusiform nuclei, and round/polygonal cells, often with rounded or indented nuclei. In addition, 51 cases showed pleomorphic, often multinucleated cells. Osteoclasts, intranuclear vacuoles, and mitoses occurred in 14, 47, and 27 cases, respectively. Thus, most high-grade LMSs have cytologic features that allow diagnosis of sarcoma. Ancillary studies can confirm the diagnosis of LMS and help in the correct interpretation of predominant spindle-cell or epitheloid-cell smears resembling neurilemoma or carcinoma, respectively.

Biallelic somatic inactivation of the NF1 gene through chromosomal translocations in a sporadic neurofibroma

Neurofibroma is a benign tumor originating from Schwann cells in peripheral nerve sheaths and may occur as a sporadic tumor or as part of the dominantly inherited tumor syndrome NF1. NF1 is caused by constitutional mutations in the NF1 gene, located in chromosome band 17q11. Whereas the involvement of the NF1 gene in neurofibroma development in NF1 patients has been fairly well characterized, the significance of inactivation of this gene in sporadic neurofibromas remains less well investigated. Inactivation of both copies of NF1 has been described in a few neurofibromas from NF1 patients, and LOH at the same locus has been reported in additional cases. In the present study, we report the cytogenetic and molecular cytogenetic findings in a sporadic neurofibroma that at G-banding analysis showed a translocation between one chromosome 2 and the long arms of both copies of chromosome 17. FISH analysis using a set of 3 BAC clones covering the entire coding region of NF1 revealed the complete loss of one allele and the deletion of the 5' portion of the second allele as a result of 2 translocation events. To the best of our knowledge, this represents the first demonstration of a somatic biallelic inactivation of the NF1 gene in neurofibroma, providing further evidence for the importance of NF1 inactivation also in sporadic neurofibromas.

Core-needle biopsy performed by the cytopathologist: a technique to complement fine-needle aspiration of soft tissue and bone lesions

BACKGROUND

Fine-needle aspiration cytology (FNAC) is gaining increased popularity in the diagnosis of musculoskeletal lesions; and, in many patients, a definitive diagnosis can be rendered from aspiration smears alone. The main limitation of FNAC of soft tissue and bone neoplasms is in the evaluation of tissue architecture. In addition cytologic specimens are not always adequate for ancillary studies.

METHODS

A consecutive series of 130 patients with soft tissue and bone lesions was examined by core-needle biopsy (CNB) performed by a cytopathologist in conjunction with FNAC. The findings of this combined diagnostic approach were compared with histologic diagnoses made on surgical biopsies and resected specimens from 86 patients. Adequate follow-up was available in all patients.

RESULTS

FNAC combined with CNB correctly could identify 77 of 78 malignant lesions and 50 of 52 benign lesions. Only seven patients underwent incisional biopsy. The tumor subtype was determined correctly in 30 of 39 patients (77%) and the malignancy grade was determined in 35 of 39 patients (90%) with primary soft tissue and bone sarcomas compared with the biopsy or operative specimens.

CONCLUSIONS

FNAC of musculoskeletal tumors/lesions complemented with CNB combined cytomorphology with tissue architecture and ancillary procedures. In the current study, obtaining FNAC as well as CNB at the same clinic visit and by the cytopathologist made preliminary diagnosis on the day of referral possible. This speeded diagnosis increased the number of correct diagnoses and usually enabled correct subtyping and malignancy grading of sarcomas.

Fine-needle aspiration of ganglioneuroma

Ganglioneuroma is a rare soft tissue neoplasm, arising most frequently in the mediastinum or retroperitoneum in children and young adults. Correct evaluation of this lesion is of crucial importance, as there are some malignant neoplasms that have similar clinical presentations. As reports of the cytologic appearance of ganglioneuroma are few, the author describes the cytologic features of three patients examined initially by fine-needle aspiration (FNA) with correlation to histology and clinical data. This paper shows that the cytologic features of ganglioneuromas can be diagnostic if both spindle cells and ganglion cells are present in smears. The absence of immature cells and necrosis/inflammation differentiates ganglioneuromas from their malignant counterparts, ganglioneuroblastomas and neuroblastomas. Immunocytochemistry can help to establish the neurogenic origin of the tumor cells.

Improved prognostication in soft tissue sarcoma: independent information from vascular invasion, necrosis, growth pattern, and immunostaining using whole-tumor sections and tissue microarrays

In 140 mixed primary soft tissue sarcomas with a median follow-up of 6 years, the prognostic importance of tumor size, tumor depth, grade, necrosis, vascular invasion, and peripheral growth pattern (pushing versus infiltrating) was evaluated on whole-tumor sections. Immunohistochemical expression of Ki-67, p53, cyclin A, bcl-2, beta-catenin, CD44, and P-glycoprotein was determined using tissue microarray from the peripheral growth zone. Local recurrences developed in 17% of the patients and correlated with necrosis, vascular invasion, and cyclin A expression. No local recurrence developed in tumors with a pushing growth pattern, regardless of tumor grade and depth. Metastasis developed in 39% of the patients. Vascular invasion was identified in 36% of the tumors and was the strongest prognostic factor for metastasis with a hazard ratio of 3.5. Growth pattern and tumor necrosis were also strong prognostic factors for metastasis, whereas malignancy grade, tumor size, and tumor depth did not have any independent prognostic value. Immunostaining showed independent prognostic information for Ki-67, beta-catenin, CD44, and P-glycoprotein. The results indicate that whole-tumor sections could facilitate identification of vascular invasion, necrosis, and peripheral growth pattern and that immunohistochemical profiling from the growth zone also provides independent prognostic information for metastasis in soft tissue sarcoma.

Molecular cytogenetic characterization of an ins(4;X) occurring as the sole abnormality in an aggressive, poorly differentiated soft tissue sarcoma

Cytogenetic and fluorescence in situ hybridization (FISH) analysis of an aggressive undifferentiated soft tissue sarcoma diagnosed as primitive neuroectodermal tumor (PNET) revealed an insertion ins(4;X)(q31-32;p11p22) as the sole aberration. To identify the molecular genetic consequences, contigs of bacterial artificial chromosomes (BACs) covering Xp11-p22 and 4q31-32 were constructed. The breakpoint in Xp22 was considered unlikely to be of pathogenetic significance, as it was very close to the Xp telomere, a region devoid of known or predicted genes. The breakpoint in Xp11 was mapped within a BAC clone containing BCOR, encoding a BCL6 (B-cell lymphoma 6)-interacting protein that may influence apoptosis, as the only known gene. FISH analysis with three overlapping clones on normal chromosomes 4 disclosed that the insertion of Xp11 material in der(4) was accompanied by a deletion of chromosome 4 material. Only a predicted gene (XM_094074) was shown to be partially included in the deletion. This gene displays a high similarity with the gene encoding the embryonic blastocoelar extracellular matrix (ECM) protein in sea urchin, which is involved in the migration of the primary mesenchyme cells during embryogenesis. Our results suggest that BCOR and/or an ECM-like protein could be involved in the pathogenesis of a subgroup of PNET or PNET-like sarcomas.

Fine-needle aspiration of primary osteosarcoma: A cytological-histological study

This study aims to determine the diagnostic accuracy of fine-needle aspiration (FNA) evaluation of primary osteosarcoma (OS) and to review diagnostic criteria and adjunctive methods that can contribute to a confident diagnosis of OS in cytological smears. We evaluated FNA smears of OS in 59 patients for the following: cytomorphology and occurrence of osteoid, usefulness of adjunctive methods in evaluation of FNA smears and correspondence of FNA to the clinical data, and the histological features of excised tumors. Reliable cytological criteria of malignancy were found in 49 smears of high-grade OS. These criteria, correlated with radiographic studies and complemented by ancillary techniques, allowed diagnosis of OS or suspicion of OS in 44 cases. An additional four smears were diagnosed as sarcoma and one case was diagnosed erroneously as being carcinoma metastasis. There were no false positive or false negative diagnoses. We conclude that FNA smears from high-grade OS have characteristic features, which together with clinical and radiological data and ancillary studies allow correct diagnosis in most tumors.