Radiologic-Pathologic Correlations of Fibrosarcomatous Dermatofibrosarcoma Protuberans With Various Histological Features on Enhanced MRI and PET/MRI

Increased 68 Ga-FAPI Uptake in Dermatofibrosarcoma Protuberans

ABSTRACT

A 47-year-old woman presented with a 6-month history of palpable masses in the right hip. The patient was subsequently enrolled in our clinical trial of 68 Ga-FAPI PET/CT study on tumors. Intense 68 Ga-FAPI activities were noted in the right hip lesions, suggestive of malignancies. Pathological examination using tissue obtained on surgical resection rendered a diagnosis of dermatofibrosarcoma protuberans.

Role of ultrasound in the diagnosis of primary and recurrent dermatofibrosarcoma protuberans

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare, low- to intermediate-grade sarcoma, which represents a diagnostic imaging challenge. This study aimed to analyze the clinical and ultrasound features of primary and recurrent DFSP to improve the diagnosis.

METHODS

Clinical, imaging, and pathological data from a total of 58 patients (23 patients with primary DFSP and 35 patients with recurrent DFSP) were retrospectively reviewed.

RESULTS

There was no statistically significant difference in age, sex, tumor size, or echogenicity between the two groups. Most of the primary DFSP lesions involved the overlying dermis and hypodermis, while most of the recurrent DFSP lesions were fixated to more deeply seated structures at the original surgical incision. Red nodules on the skin were found more frequently in the primary group. There were statistically significant differences in the type of lesion and ultrasound tumor morphology (p < 0.050). The lesions in the primary group showed more tentacle-like projections or a "claw" sign, while the lesions in the recurrent group were more commonly oval, lobulated, and irregularly shaped. Hypervascularity was common in both groups.

CONCLUSIONS

For primary DFSP, a slow-growing, red nodule on the skin involving the overlying dermis and hypodermis, more frequently a hypoechoic mass with tentacle-like projections or a "claw" sign, was observed. For recurrent DFSP, palpable subcutaneous nodules or subcutaneous masses at the original surgical incision and oval, lobulated, and irregularly shaped lesions were more commonly observed. This may be useful for improving diagnostic accuracy.

Dermatofibrosarcoma protuberans: the diagnosis of high-grade fibrosarcomatous transformation

OBJECTIVES

Dermatofibrosarcoma protuberans (DFSP) is an intermediate-grade tumour which may undergo fibrosarcomatous transformation to a high-grade sarcoma (DFSP-FST). DFSP-FST requires wide local resection, and therefore, pre-operative identification is important. The aims of this study are to see if DFSP and DFSP-FST can be differentiated based on MRI appearances, and to determine the ability of ultrasound-guided core needle biopsy (US-CNB) to identify DFSP-FST.

MATERIALS AND METHODS

Retrospective review of patients with a histological diagnosis of DFSP with/without transformation to DFSP-FST. Patient age, gender, lesion location and maximal size were recorded, as were several MRI features. MRI studies were reviewed independently by 2 musculoskeletal radiologists and the assessed features were then compared with final surgical resection histology. Histological results of US-CNB were also compared with final surgical pathology.

RESULTS

A total of 42 patients were included, 26 males and 16 females with a mean age of 41.3 years (range 3-78 years). The upper limb was involved in 12 cases, the lower limb in 17 and the trunk in 13. Final surgical histological diagnosis was DFSP in 21 (50%) cases and DFSP-FST in 21 (50%) cases. Mean tumour dimension for DFSP was 32 mm and DFSP-FST 68 mm (p < 0.001). MRI features indicative of DFSP-FST included multi-lobular morphology (p = 0.03), T2W hypointensity compared with fat (p = 0.03), internal flow voids (p = 0.03) and peri-tumoral oedema (p < 0.001). Only 3 cases of DFSP-FST were correctly diagnosed on US-CNB.

CONCLUSIONS

Various MRI findings can suggest a diagnosis of DFSP-FST, but US-CNB is unreliable at identifying high-grade fibrosarcomatous transformation.

A review of non-invasive imaging in extramammary Paget's disease

Extramammary Paget's Disease (EMPD) is a rare intraepithelial adenocarcinoma that classically manifests with pruritic, erythematous and scaling plaques. The clinical picture frequently mimics inflammatory or infectious conditions and is thus commonly misdiagnosed. The assessment of tumour margins is equally challenging as tumours have a propensity to spread beyond clinically visible boundaries. Appropriate non-invasive diagnostic tools can assist in the early detection, diagnosis and management of EMPD. This paper will review the literature on non-invasive imaging modalities used in EMPD. Articles from the PubMed database were selected based on relevance to the topic of this review. Articles that were not specific to EMPD and non-invasive imaging were excluded. Search strategy is further described in the methods section below. Eighteen articles were selected for this review: six PET/CT, five reflectance confocal microscopy (RCM), two photodynamic diagnosis (PDD), two dermoscopy, two MRI and one optical coherence tomography (OCT) paper(s). Dermoscopy, PDD, RCM and OCT can help to distinguish malignant conditions, including EMPD, from benign conditions. RCM and OCT can identify atypical cells in real-time, and have the potential to improve the accuracy of surgical margins intraoperatively and overall management. Distinctive confocal characteristics of EMPD have been described using RCM. The sensitivity and specificity of these findings require additional validation. Radiographic techniques also play a central role in the diagnosis of EMPD and assessment of disease spread. PET/CT and MRI can detect primary disease, nodal and distant metastases, with superior delineation of disease spread on MRI. Limitations of PET/CT are mainly related to primary tumour thickness, and size and FDG-avidity of nodal and distant metastases. Limitations of MRI include the fact that few studies have examined its use in EMPD; additional research is warranted. Randomized controlled trials and large prospective studies evaluating the use of non-invasive imaging in EMPD are needed.

Review of the pathophysiology, diagnosis, and therapy of vulvar leiomyoma, a rare gynecological tumor

The objective of this article is to discuss the pathophysiology, diagnosis, differential diagnosis, and therapy of vulvar leiomyoma. We performed a review of all English-language reports of vulvar leiomyoma published in PubMed from 1978 to 2015 using the following search terms: “vulval leiomyoma,” “vulvar leiomyoma,” “vulval smooth muscle tumor,” and “external genitalia smooth muscle tumor.” Vulvar leiomyomas, which are rare benign monoclonal tumors, most commonly occur in the fourth and fifth decades of life. The genetics of vulvar leiomyoma remain undefined. Three principal histological patterns have been identified: spindled, epithelioid, and myxoid. Imaging tests such as ultrasound, endoscopic ultrasound, and magnetic resonance imaging are used in diagnosis. Surgical excision is the only curative treatment for vulvar leiomyomas. Establishment of a full differential diagnosis list and correct final diagnosis before surgery are essential for optimal clinical management. Although recurrence of vulvar leiomyoma is extremely rare, long-term follow-up of all cases is advisable.

18F-FDG PET/CT of Secondary Epithelioid Angiosarcoma of the Proximal Femur in a Patient With Polyostotic Fibrous Dysplasia

Fibrous dysplasia rarely transforms into a secondary malignancy. We present the PET/CT findings at pretreatment and posttreatment in an exceedingly rare case of epithelioid angiosarcoma of the bone secondary to polyostotic fibrous dysplasia.