Fine-needle aspiration of primary and recurrent dermatofibrosarcoma protuberans

Diagnostic performance of fine-needle aspiration in soft tissue tumors: Application of the World Health Organization System for Reporting Soft Tissue Cytopathology and risk of malignancy assessment

BACKGROUND

Recently, a new World Health Organization Reporting System for Soft Tissue Cytopathology (WHO System) was introduced. To analyze the value of this system, routine fine-needle aspiration soft tissue tumor (STT) cases were reviewed.

METHODS

Cytology samples of STTs collected between 1954 and 2022 at the Institut Curie were used (2214 cases, including 1376 primary tumors). All specimens were classified according to the predominant cytomorphological pattern and the WHO System. The diagnostic accuracy and risk of malignancy (ROM) in each category were calculated.

RESULTS

Final diagnoses revealed 1236 malignancies and 978 benign or low-risk tumors. The original cytological evaluation led to 21 false-negative results (0.85%) and 29 false-positive results (1.17%). Sensitivity, specificity, positive predictive value, and negative predictive value were 98.3%, 92.1%, 97.5%, and 94.2%, respectively. Overall diagnostic accuracy was 94.2%. The ROM calculated according to the WHO System was 29.87%, 2.49%, 39.62%, 51.43%, 68.42%, and 97.69% in the nondiagnostic, benign, atypical, soft tissue neoplasm of uncertain malignant potential, suspicious for malignancy, and malignant categories, respectively; however, it varied broadly depending on the morphological pattern (62.78% in spindle cell tumors, 84.58% in myxoid tumors, 3.00% in lipomatous tumors, 78.15% in epithelioid tumors, 94.26% in pleomorphic tumors, and 100% in round cell tumors).

CONCLUSIONS

Cytology of STTs is a powerful diagnostic method. Some cytological patterns overlap in different morphological groups, and the possibility of false-negative and false-positive diagnoses may persist. This analysis evidenced utility of the WHO System, especially when combined with morphological pattern assessment. Subclassification in particular diagnostic categories allowed for calculation of the ROM, which is crucial for optimal patient management.

Recurrent Dermatofibrosarcoma Protuberans of the Head and Neck: a Case Series

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma that develops from dermal fibroblasts and spreads within the dermis and subcutaneous fat. It is locally aggressive, with a high local recurrence rate after excision but has extremely low metastatic potential. In the case of recurrent tumors, surgical excision with adequate margins is the gold standard treatment and may require adjuvant radiotherapy or chemotherapy in some cases. We conducted a retrospective analysis of individuals with dermatofibrosarcoma protuberance of the head and neck region that had treatment at our facility between 2016 and 2021. We gathered the data on the surgical techniques, reconstructive techniques used, histopathological features, adjuvant therapy, and outcomes. We treated three patients with head and neck dermatofibrosarcoma protuberance: one scalp lesion and two on the cheek. All three patients had recurrent tumors, two of whom were treated elsewhere for the primary lesion. One patient underwent surgery for a benign spindle cell tumor of the right cheek, but a final histopathological examination revealed dermatofibrosarcoma protuberance, and the tumor recurred within 3 months. The duration of recurrence is between 3 and 24 months. The size of the tumor ranges from 7.2 to 10.5 cm. The wide local excision margins range from 2 to 4 cm. Reconstruction ranges from split skin graft to regional flap. Inadequate margins raise the possibility of local recurrence in dermatofibrosarcoma protuberance.

Comparison of 68Ga-FAPI and 18F-FDG PET/CT in Dermatofibrosarcoma Protuberans

ABSTRACT

Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma with a high recurrence rate. Herein, we present 68Ga-FAPI and 18F-FDG PET/CT findings of dermatofibrosarcoma protuberans in a 45-year-old man. Dermatofibrosarcoma protuberans only shows limited FDG uptakes on 18F-FDG PET/CT, but demonstrated intense tracer uptakes on 68Ga-FAPI PET/CT. In this case, 68Ga-FAPI was superior to 18F-FDG PET/CT in detecting dermatofibrosarcoma protuberans.

Applications of Ancillary Testing in the Cytologic Diagnosis of Soft Tissue Neoplasms

Soft tissue neoplasms are diagnostically challenging, although many advances in ancillary testing now enable accurate classification of fine-needle aspiration biopsies by detection of characteristic immunophenotypes (including protein correlates of molecular alterations) and molecular features. Although there are many useful diagnostic immunohistochemical markers and molecular assays, their diagnostic utility relies on correlation with clinical and morphologic features, judicious application, and appropriate interpretation because no single test is perfectly sensitive or specific. This review discusses applications of ancillary testing for commonly encountered soft tissue neoplasms in cytopathologic practice in the context of a pattern-based approach.

Dermatofibrosarcoma: a rare neoplasm of skin

A 25-year-old lady presented with a small pea-sized lesion on left side of her neck, anteriorly. There was no history of any other lesion on her body. She was medically fit otherwise. An excision was planned, after taking consent from her, which was performed under local anaesthesia as a day procedure. Her postoperative recovery was uneventful. Histopathology showed dermatofibrosarcoma protuberance which is an extremely rare skin tumour. She was further investigated for metastasis. Her CT scan of chest, abdomen and pelvis was performed which showed prominent thymus. Other than this finding, no other abnormality was found in CT scan.

Fine-needle aspiration of primary and recurrent benign fibrous histiocytoma: classic, aneurysmal, and myxoid variants

There is a limited number of correlative cytopathological studies of fibrous histiocytoma (FHC). To better define cytopathological criteria of diagnosis, we have reviewed fine-needle aspirates (FNA) from 36 FHCs (32 classical, 1 myxoid, and 3 aneurysmal variants on corresponding histological sections). Original cytological diagnoses were benign in 33 (91.7%) cases (22 accurate) and false positive in 3 (8.3%) cases. All smears were surprisingly homogenous and composed of histiocytic cells with finely vacuolated cytoplasm in 27 (75%) cases, small regular spindle cells in 25 (69%) cases, and giant cells in 17 (47%) cases. Histiocytic cells were attached to vascular structures in 9 (25%) cases. Slight cytonuclear atypia was seen in five (14%) cases. Three (8.3%) cases showed numerous siderophages. In two (5.6%) cases, there were abundant inflammatory backgrounds and in one (3%) case there was a scant myxoid background. Storiform patterns, round cells, prominent atypia, necroses, or mitotic figures were not seen. FHC should be differentiated from other benign, low- and intermediate-grade spindle-cell neoplasms such as low-grade fibrosarcoma, dermatofibrosarcoma protuberans, nodular fasciitis, spindle-cell malignant melanoma, and monophasic synovial sarcoma. Some cases may be misinterpreted as malignant, especially in cases of recurrence or in patients with a cancer history.

FNA diagnosis of dermatofibrosarcoma protuberans

Fine-needle aspiration (FNA) features of primary and recurrent dermatofibrosarcoma protuberans (DFSP) in two patients were evaluated and correlated to ancillary studies and clinical data. The tumors developed in the skin and subcutaneous tissue of the back in both patients. The cytological findings included clusters and dispersed uniform or slightly atypical spindle cells, collagenous matrix, and, in one case, cell clusters with a storiform pattern. Both tumors were diagnosed correctly when FNA was complemented by ancillary studies (immunostaining) and clinical data. FNA features alone are not sufficiently characteristic to permit a confident diagnosis of DFSP. Correct diagnosis requires an awareness of the clinical history and the use of ancillary studies.

Dermatofibrosarcoma protuberans

In the current review, the authors set out to discuss the natural history and treatment of dermatofibrosarcoma protuberans (DFSP), a rare indolent cutaneous tumor. Approximately 10-15% of all DFSPs contain areas of fibrosarcoma (DFSP-FS), and such cases tend to exhibit more aggressive behavior. The optimal treatment for DFSP is resection with wide margins; the likelihood of local control associated with this procedure exceeds 90%. The probability of regional or distant metastases is </= 5%. Patients with positive or close surgical margins have an elevated risk of local recurrence after resection alone; however, postoperative radiotherapy results in local control rates of >/= 85% in such patients. Postoperative radiotherapy also is indicated in the rare event that a patient has unresectable macroscopic disease. Experience with the use of radiotherapy alone to treat macroscopic disease is limited.