Fine needle aspiration cytology of myxoid liposarcoma; a study of 18 tumours

Myxoid Soft Tissue Tumors: A 20-Year Experience on Fine Needle Aspiration with Application of the Proposed WHO Reporting System for Soft Tissue Cytopathology

INTRODUCTION

Myxoid soft tissue tumors represent a heterogenous group of neoplasms. The study presented our experience on cytopathology of myxoid soft tissue tumors on fine needle aspiration (FNA) and aimed to apply the recently proposed WHO system for reporting soft tissue cytopathology.

MATERIAL AND METHODS

We performed a 20-year retrospective search of our archives to identify all FNAs performed on myxoid soft tissue lesions. All cases were reviewed, and the WHO reporting system was applied.

RESULTS

129 FNAs performed in 121 patients (62 males; 59 females) showed a prominent myxoid component, accounting for 2.4% of all soft tissue FNAs. The FNAs were performed on 111 (86.7%) primary tumors, 17 (13.2%) recurrent tumors, and one (0.8%) metastatic lesion. A spectrum of non-neoplastic and neoplastic lesions including both benign and malignant neoplasms was identified. Overall, the most common tumors identified were myxoid liposarcoma (27.1%), intramuscular myxoma (15.5%), and myxofibrosarcoma (13.1%). The sensitivity and specificity of FNA regarding the nature of the lesion (benign vs. malignant) were 98% and 100%, respectively. When the WHO reporting system was applied, the frequency of the categories was as follows: benign (7.8%), atypical (34.1%), soft tissue neoplasm of uncertain malignant potential (18.6%), suspicious for malignancy (3.1%), and malignant (36.4%). The risk of malignancy calculated in each category was as follows: benign (10%), atypical (31.8%), soft tissue neoplasm of uncertain malignant potential (50%), suspicious for malignancy (100%), and malignant (100%).

CONCLUSION

A diverse group of non-neoplastic and neoplastic lesions can show a prominent myxoid component on FNA. The WHO reporting system for soft tissue cytopathology is easily applicable and appears to correlate well with the malignant potential of myxoid tumors.

Cytomorphologic findings of low-grade fibromyxoid sarcoma

INTRODUCTION

Low-grade fibromyxoid sarcoma (LGFMS) is a rare fibroblastic tumor characterized by a prolonged clinical course and malignant biological behavior. Given its deceptively bland cytomorphology, a diagnosis can be quite challenging notably on fine-needle aspiration (FNA). In an attempt to shed light on some of the distinctive cytomorphologic characteristics, this study was conducted to review all cases of LGFMS in our database, correlating available clinical data, immunohistochemical findings, and molecular analysis.

MATERIALS AND METHODS

This series included 20 FNAs from 18 patients with a histologically confirmed LGFMS diagnosis from 3 large academic institutions. Detailed cytomorphologic analysis for each case was documented in conjunction with corresponding clinical characteristics and provided ancillary testing.

RESULTS

Out of 14 adequate FNA samples, 9 (64.2%) demonstrated a mixture of fibrous and myxoid pattern; the majority of cases were composed of deceptively bland tumor cells with rare nuclear pleomorphism and nuclear membrane irregularities. A MUC4 immunostain was performed on 5 specimens; all tested positive (100%). FUS rearrangement was detected in 4 out of 5 cases (80%). Follow-up information revealed 5-year recurrence in 1 case and metastatic disease in 2 cases, to the lung/pleura (8 years) and fourth rib (1 year), respectively.

CONCLUSIONS

The presence of bland spindle cells and associated with myxoid matrix material, in the appropriate clinical setting, can suggest LGFMS and direct additional confirmatory testing. A definitive diagnosis of LGFMS on FNA requires adequate sampling, familiarity with key cytomorphologic features, acquisition of diagnostic material for a cell block preparation and ancillary testing, and clinicoradiologic correlation.

Myxoid liposarcoma: Fine-needle aspiration cytopathology in the molecular era. A report of 24 cases

INTRODUCTION

Application of fine-needle aspiration (FNA) biopsy to soft tissue tumors remains underutilized in North America. Myxoid liposarcoma (LPS), the second most common subtype of LPS, is characterized primarily by t(12;16)(q13;p11) which is amenable to FISH analysis using a break-apart probe for DDIT3. Little is known regarding FISH testing for DDIT3 on cytologic specimens. We report our FNA experience with myxoid LPS and application of this molecular probe.

MATERIALS AND METHODS

Specimens retrieved from our cytology database used search codes for myxoid LPS. Tissue files were searched for any cases with corresponding FNA biopsies. FNA biopsy was performed using a standard technique.

RESULTS

From 24 FNA cases of myxoid LPS (mean age = 52 years), a specific diagnosis was made in 87.5%. Two cases were diagnosed as spindle/round cell neoplasm, and 1 as suspicious for myxoid LPS. There were 2 false positive diagnoses and no false negatives. Nearly all cases arose in the extremities; thigh being most common. Principal cytologic features consisted of discrete myxocellular microfragments, a plexiform capillary pattern, and variable number of univacuolated lipoblasts. Uniformly banal ovoid nuclei were randomly scattered within myxocellular microfragments. FISH analysis for DDIT3 rearrangement from unstained smears and/or cell-block was positive in 13 cases, and unsuccessful in 3, with no false positive/false negative results.

CONCLUSION

Myxoid LPS is diagnosable in a high percentage of cases using FNA biopsy alone. Confirmatory FISH analysis for DDIT3 is not only possible, but also valuable for correctly recognizing this neoplasm.

Fine-needle aspiration characteristics of hibernoma

BACKGROUND

Hibernoma is a rare, benign lipomatous tumor with features of brown fat. The preoperative diagnosis of hibernoma is difficult at times because its clinical, radiographic, and fine-needle aspiration (FNA) characteristics overlap with those of liposarcoma.

METHODS

The preoperative FNA findings of eight surgically excised hibernomas from seven patients (three men and four women, ages 24-60 years) were reviewed. The cytologic features were compared with the histologic features of the corresponding surgical specimens as well as lipomatous tumors and other lesions that may cause confusion in the differential diagnosis.

RESULTS

The FNA cytologic features of the hibernomas were found to correspond well with their histologic appearance. The FNA findings included small, round, brown fat-like cells with uniform, small cytoplasmic vacuoles and regular, small, round nuclei; delicate branching capillaries; and variable numbers of mature fat cells.

CONCLUSIONS

The FNA cytologic features of hibernoma are characteristic and useful in the preoperative investigation of lipomatous tumors, particularly with regard to excluding a diagnosis of liposarcoma.

The value of fine-needle aspiration biopsy in the differential diagnosis of adult myxoid sarcoma

BACKGROUND

The usefulness of fine-needle aspiration biopsy (FNAB) for the histologic subtyping of specific sarcomas still is somewhat controversial but is becoming increasingly popular in the U.S.

METHODS

To determine the accuracy and usefulness of FNAB in the differential diagnosis of myxoid sarcoma, the authors retrospectively reviewed 18 FNAB specimens (16 primary tumors, 1 local recurrence, and 1 metastasis) in 18 patients. The study sample included myxoid/round cell liposarcoma in six patients, myxofibrosarcoma in six patients, myxoid chondrosarcoma in five patients, and myxoid leiomyosarcoma in one patient.

RESULTS

All but one tumor were recognized correctly as malignant. With regard to primary tumors, a specific cytologic diagnosis was rendered in 13 of 16 patients (81%). Problematic areas included the diagnosis of high grade myxofibrosarcoma with minimal amounts of myxoid stroma, myxoid liposarcoma with a predominant round cell component, and the single case of myxoid leiomyosarcoma.

CONCLUSIONS

FNAB represents a valuable diagnostic tool for the differential diagnosis of myxoid sarcoma, especially myxofibrosarcoma, low grade myxoid liposarcoma, and myxoid chondrosarcoma. Due to its prognostic and therapeutic significance, the presence of a predominant round cell component in myxoid liposarcoma should be documented adequately. Other sarcomas (e.g., leiomyosarcoma) rarely may exhibit a prominent myxoid stroma and therefore should be considered in the differential diagnosis of adult myxoid sarcoma.

Myxomatous soft tissue tumors: correlation of cytopathology and histopathology

A small, uncommon group of soft tissue tumors are distinguished by their unique and consistent ability to produce an overwhelming abundance of myxoid ground substance along with the proliferating cells that constitute the tumor. Grossly, all these neoplasms have a variable gelatinous quality. Because of the voluminous stroma, most of these tumors have some findings that overlap with one another. Nonetheless, each tumor has a composite set of morphologic, immunophenotypic, ultrastructural, and genotypic features exclusive to itself. Because soft tissue masses are not a frequent site of fine-needle aspiration, the cytopathology of this set of tumors is vastly unappreciated, both in the literature and in day-to-day practice. The aim of this review is to detail the salient light microscopic findings of this group of six major myxoid soft tissue tumors, to correlate the cytopathology (particularly as obtained using the fine-needle aspiration biopsy technique) with its histopathologic counterparts, and to discuss the limitations of both cytologic and histologic methods. This cytohistopathologic correlation should assist the reader in the diagnosis of myxoid tumors of soft tissue.

Cytomorphologic features of fine-needle aspiration of liposarcoma

The cytomorphologic features of fine-needle aspirates (FNA) of liposarcomas have not been fully characterized. In the current study, we attempted to identify cytological attributes of liposarcoma in FNA. Twelve FNAs of histologically proven liposarcomas were used for this study. They included 10 myxoid and two well-differentiated liposarcomas. Four cytological criteria were chosen for evaluation. These included a complex capillary network, increased cellularity, the presence of a metachromatic stroma for myxoid liposarcoma, and finally the identification of lipoblasts. Eighteen FNAs of lipomas and 17 FNAs of nonlipomatous soft-tissue sarcomas were used as controls for evaluation of the same features. The diagnosis of liposarcoma had been rendered on FNA in 7 cases (58%). The diagnosis was suggested in 3 cases (25%), and a suggestion of sarcoma was rendered in 2 cases. Complex capillary networks were identified in 9 of 12 cases (75%); this was seen in 8 of the 10 myxoid liposarcomas and 1 of the 2 well-differentiated neoplasms. Increased cellularity was seen in 7 of 12 cases (58%), metachromatic stroma was seen in 3 of 12 cases (25%), and lipoblasts were identified in 4 of 12 cases (33%). None of the lipomas or sarcomas exhibited a complex capillary network. When capillaries were identified in lipomas, they were straight, with minimal branching. The lipomas did not show evidence of increased cellularity in any cases. Metachromatic stroma was more frequently seen in the nonlipomatous sarcomas than in the liposarcomas. No lipoblasts were identified in any of the control FNAs.

Fine-needle aspiration cytology of ganglion cysts

Ganglion cyst is a relatively common lesion resulting from mucoid, cystic degeneration of soft tissues adjacent to a joint space. Aspiration of cyst contents has been increasingly advocated as a diagnostic and, in some instances, therapeutic modality. We report the fine-needle aspiration cytologic (FNAC) findings from seven cases of ganglion cyst. These include the aspiration of thick, gelatinous fluid and a smear comprised of rare histiocytes embedded in a mucoid matrix. Although these findings are nonspecific, we believe that in the appropriate clinical setting, the diagnosis of ganglion cyst can be made with confidence by FNA.

Metastatic liposarcoma in the adrenal gland: report of two cases diagnosed by fine-needle aspiration

Fine-needle aspiration is now well established in the investigation of retroperitoneal masses. Many of these lesions are first detected in the course of radiological surveys of patients with known or suspected malignancy. It can be difficult to diagnose sarcomas on fine-needle aspiration material as many of these tumour do not show cytological features of malignancy. We describe two cases of metastatic liposarcoma confidently diagnosed on the basis of characteristic cytological features seen in material aspirated from metastatic adrenal tumours.