Accuracy of clinical diagnosis, imaging methods, and biopsy in tumours and pseudo-tumours of the hand

Introduction

Hand tumours may originate from soft tissues or bone. Imaging methods are useful for defining their structural characteristics, accurately determining their anatomic locations, and aiding in confident or tentative diagnoses. In cases of diagnostic uncertainty or suspected malignancy, percutaneous biopsy under imaging guidance is a safe option.

Bone tumours in the hands and fingers account for 6% of benign tumours and 0.5% of malignant tumours, with enchondroma and chondrosarcoma being the most common benign and malignant types, respectively (1). Soft tissue tumours affecting the hands and fingers comprise 15% of benign tumours and 4% of malignant ones (2). Ganglion cyst is the most frequent benign mass. Giant cell tumour of the tendon sheath, lipoma, and haemangioma are the most frequent tumours. Malignant soft tissue tumours are more prevalent than their bone counterparts and may include squamous cell carcinoma, sarcomas, lymphoma, and metastases.

Conditions like inflammatory or infectious processes may also cause swelling or lumping of the hand, and imaging can play a role in their characterization, differential diagnosis, and guiding biopsies when necessary (3).

The utility of imaging in bone and soft tissue tumours is well-documented in the radiological literature (4,5). However, given that most of the tumoral conditions of the hand are benign, the use of imaging in clinical practice may vary based on clinician preferences and technical availability (6).

This work is based on our institution’s experience managing the tumours and pseudotumours of the hand and wrist. We aimed to compare the diagnostic accuracy of clinical suspicion, different imaging methods and image-guided biopsy in the diagnosis of hand tumours in routine clinical scenarios. The main objective was to improve treatment protocols by emphasizing the importance of different imaging methods in the treatment of hand tumours. We present this article in accordance with the STARD reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-24-347/rc).

Methods

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). This study was approved by the Provincial Ethics Committee of Granada (approval code: TFG-EITM-2020) for reviewing medical records. Individual consent for this retrospective analysis was waived.

Patients were collected from the records of the multidisciplinary oncology board and the radiology department. Clinical and imaging reports were reviewed. For clinical or imaging accuracy analysis the main inclusion criteria were to have surgical and/or biopsy-puncture-drainage confirmation. In addition, 4 typical osteoid osteomas, in which biopsy could not be obtained during radiofrequency ablation, were included, as clinical and radiological findings in these cases are considered diagnostic (7). For biopsy accuracy analysis only biopsied cases with pathological confirmation after surgery, microbiological or analytical analysis of the sample were considered, except in 2 cases of typical osteoid osteomas treated with radiofrequency with positive biopsy, and a metastasis in which the biopsy results matched the biopsy of the primary lung tumour. These were considered as sufficient evidence for an accurate diagnosis. For clinical diagnostic accuracy, data from imaging request forms or from anamnesis and physical examinations in the medical records were reviewed. The clinical diagnosis, including all differential diagnoses considered by the clinician, was considered accurate when it matched the final pathological or surgical results.

Similarly, to define imaging diagnostic accuracy, data from radiological reports were reviewed. The diagnosis was considered correct if one of the two first differential diagnoses suggested in the conclusion of the report matched the final pathologic or surgical results.

The most significant features characterising the lesions on ultrasonography (US) (echogenicity and Doppler signal) (Figure 1), computed tomography (CT) (density, calcification) (Figure 2), and magnetic resonance imaging (MRI) (signal intensity, enhancement pattern) (Figures 3,4), were used to make a presumptive radiological diagnosis.

Figure 1 Classification of the echo graphic patterns. (A) Anechoic ganglion cyst. (B) Hypoechoic GCTTS. (C) Isoechoic giant GCTTS. (D) Hyperechoic lipoma. (E) Diffuse Doppler signal in epidermoid carcinoma. (F) Peripheral doppler signal in Schwannoma. GCTTS, giant cell tumour of tendon sheath.

Figure 2 Classification of density patterns in computed tomography. (A) Hypodense lesion in synovial chondromatosis. (B) Isodense haemangioma. (C) Hyperdense calcified lesion in Bizarre parosteal osteochondromatous proliferation. Arrows indicate the tumour.

Figure 3 Classification of signal patterns on MRI. (A) T1 hypointensity in myxoma. (B) T1 isointensity in a GCTTS. (C) T1 hyperintensity in lipoma. (D) T2 hypointensity in haemangioma. (E) T2 isointensity in GCTTS. (F) T2 hyperintensity in angioleiomyoma. MRI, magnetic resonance imaging; GCTTS, giant cell tumour of tendon sheath.

Figure 4 Enhancement patterns on MRI. (A) Heterogeneous in myxoma. (B) Homogeneous in epithelioid haemangioma. (C) Peripheral in keratoacanthoma. MRI, magnetic resonance imaging.

Ultrasound-guided biopsies were performed using automatic Tru-Cut 14 G needles with coaxial systems (Acecut^®), obtaining 3 to 5 core biopsies. Ultrasound-guided ganglion drainage was performed using Abbocath 14 to 19 G catheters. After drainage, a mixture of anaesthetic and 40 mg of triamcinolone was introduced. CT-guided biopsy was also performed with a co-axial system: automatic 14 G tru-cut when the cortex was thinned or a bone trephine, 13 or 15 G, when the cortex was thicker. One to three core biopsies were obtained.

Statistical analysis

Statistical analyses were performed using IBM SPSS Statistics (v. 19.0) and R (v. 4.3.2.) software. Quantitative variables are expressed as means ± standard error of the mean or percentages. Bivariate analyses between continuous and cathegorical variables were performed using Student’s t-test, and chi-squared tests. All statistical analyses were two-tailed, and P values <0.05 were considered statistically.

For accuracy estimation of the imaging-guided core biopsy, we considered a true positive (TP) when the biopsy diagnosis matched the pathology report of the surgical specimen. Three non-operated cases were also considered TPs only with the core biopsy (1 metastasis matching the primary lung tumour, and 2 osteoid osteomas with typical imaging findings and successfully treated by radiofrequency ablation). False positives (FPs) were considered if the diagnosis was positive for tumour, but no tumour was found at surgery or follow-up. True negatives (TNs) were considered when the biopsy was negative for tumour and another diagnosis, such as infection or inflammation, was proven. Finally, we considered as false negatives (FNs) when surgery proved the presence of a tumour and the biopsy was negative, or when the type of tumour diagnosed by biopsy did not match the pathological diagnosis after surgical removal.

The core biopsy sensitivity was calculated as TPs/TPs + FNs, specificity as TNs/TNs + FPs, and accuracy as TPs + TNs/TPs + FPs + TNs + FNs.

Results

We retrospectively reviewed 198 consecutive cases referred to the Hospital Virgen de las Nieves with a clinical suspicion of hand tumours over the past 10 years (January 2014 to December 2023). Twenty-three patients were excluded because of incomplete data (Figure 5). Therefore, 175 patients were included in the study. Twenty-nine soft tissue lesions were confirmed as ganglion cysts by puncture under ultrasound guidance, although 5 were also operated after recurrence and confirmed pathologically (Figure 6). The 24 non operated ganglion cyst were only included in the imaging accuracy analysis. Four cases of bone tumours were osteoid osteomas successfully treated by radiofrequency thermal ablation, but without pathological confirmation. These were included only in the imaging accuracy analysis (Figure 6). In total, 147 patients received a pathological or microbiological diagnosis following surgery (n=124) and/or imaging guided core biopsy (n=62, 14 CT-guided and 48 ultrasound-guided) or fine needle aspiration (n=1). Eventually, of the 175 cases, 21 resulted to be infectious, metabolic, or inflammatory processes (Table 1), and 154 were diagnosed as tumours or pseudotumors of the hand, 101 from soft tissues (Table 2) and 53 from bones (Table 3, Figure 5).

Figure 5 Flowchart of included cases for clinical, imaging, and biopsy accuracy. RF, radiofrequency.

Figure 6 Included cases with no pathological proof. (A) Puncture of ganglion cyst over the flexor tendon. (B) Ablation of osteoid osteoma at the middle phalanx of the thumb.

Clinical and imaging analysis

The final series comprised 175 patients, 81 men and 94 women. The mean age of the patients was 44.1±1.4 years (minimum, 6; maximum, 93), and a median of 44. There were no statistical differences in age between men and women.

The right hand was affected in 106 cases (60.6%). The most frequent locations of the lesions were the fingers (n=73), followed by the metacarpal area (n=53) and the wrist (n=49).

Table 4 presents the significant findings of bivariate analyses regarding the benignity or malignancy of the lesions. Patients with malignant bone and soft tissue tumours were older, and malignant bone and soft tissue lesions were larger in size. Malignant soft tissue tumours tend to be heterogeneous at ultrasound, predominantly isoechoic or hypoechoic, and with diffuse neovascularity. Malignant bone tumours showed an irregular contour more frequently than benign tumours.

Ultrasound was performed in 86 soft tissue tumours. Significant differences were found in the following variables: echogenicity pattern, with no malignant tumours being anechoic or echogenic; homogeneity of the lesion, with 90% of the malignant tumours being heterogeneous; and Doppler signal, with 88% of the malignant tumours showing diffuse neovascularity and 78% of benign tumours showing no Doppler signal.

No significant differences were found in MR or CT patterns between benign or malignant tumours, either in soft tissues or bone.

Of 96 cases with CT and/or radiography, 34 showed calcifications. This finding did not discriminate between benign and malignant lesions.

Imaging and clinical accuracy analysis

Table 5 depicts the accuracy of clinical assessment and imaging methods regarding the whole sample, soft tissue tumors, bone tumors, benign and malignant tumors, inflammatory processes, and some specific frequent tumors. In general, imaging methods were more accurate than clinical diagnosis, MRI was superior to ultrasound in soft tissues, and CT and MRI were equivalent in bone tumours.

Regarding soft tissues, ultrasound and MRI were highly accurate in cystic lesions, but in 67 non-cystic lesions in which both techniques were used, MRI provided an accurate diagnosis in 49 cases (73.1%) and ultrasound in 44 (65.7 %), P<0.001 (Table 6).

Biopsy accuracy analysis

The 29 punctured ganglion cysts were not included in the accuracy analysis, except for 5 of them that recurred and were operated and confirmed as ganglion cysts. The mean follow-up time after puncture was 40.8±7.0 months.

Table 7 reports the accuracy of biopsy in the whole sample and in soft tissue and bone tumours. Fifty-four out of 62 biopsied cases were included: 40 with surgical proof, 11 that resulted to be infectious or inflammatory conditions treated medically, 1 metastasis (with no surgery but matched the primary lung tumour), and 2 osteoid osteomas that were treated by radiofrequency ablation. Eight cases with no surgery were not considered in the analysis.

In soft tissue cases, we included 37 core biopsies, with 19 TPs, 13 TNs, and 5 FNs. The 13 TNs were non-tumoral inflammatory/infectious conditions. The 5 FNs were a recurrent melanoma, a recurrent epidermoid carcinoma, and a spindle cell lipoma (Figure 7) with no tumour found at biopsy sample, and 2 cases in which the pathological diagnosis of the sample did not match the pathology of the surgical specimen: an epidermal inclusion cyst on biopsy was eventually a keratoacanthoma, and a spindle cell lipoma was eventually a spindle cell haemangioma. Imaging-guided biopsy was performed in only 57% (8/14) of the malignant tumours. In the remaining (6 cases), 1 epidermoid carcinoma was biopsied in the surgical theatre, 1 was a known recurrent undifferentiated pleomorphic sarcoma, 3 (epidermoid carcinoma, synovial sarcoma, and fibromyxoid sarcoma) required surgical margin ampliation after surgery, and 2 (clear cell sarcoma and fibroblastic inflammatory sarcoma) required additional radiotherapy after surgery (Figure 8).

Figure 7 False negatives biopsies in ultrasound. (A) Axial T1 of fusocellular lipoma. (B) Ultrasound-guided biopsy. (C) Coronal T2 fat sat of recurrent melanoma. (D) Imaging guided biopsy. (E) Coronal T2 fat sat of recurrent epidermoid carcinoma. (F) US guided biopsy. US, ultrasonography.

Figure 8 Malignant cases operated without biopsy. (A) Axial T1+C of undifferentiated pleomorphic sarcoma. (B) Sagittal PD fat sat of epidermoid carcinoma. (C) Coronal STIR in synovial sarcoma. (D) Coronal PD fat sat in fibromyxoid sarcoma. (E) Axial T2 in clear cell sarcoma. (F) Sagittal PD fat sat in fibroblastic inflammatory sarcoma. PD, proton density; STIR, short tau inversion recovery.

Regarding bone cases, we included 17 core biopsies with 16 TPs and 1 TN. The TN was a tuberculous osteomyelitis. Five of the 8 malignant bone tumours were not biopsied at the radiology department. A surgical biopsy was performed in Ewing tumour. One epithelioid haemangioendothelioma was treated by postsurgical radiotherapy. In the 2 chondrosarcoma cases, no further treatment was performed, one of them due to old patient age and the other one because the surgical margin (amputation of the distal phalanx) was considered safe (Figure 9).

Figure 9 Malignant bone tumours operated without previous biopsy. (A) Coronal T1 in epithelioid hemangioendothelioma. (B) Coronal CT in metacarpal chondrosarcoma. (C) Sagittal PD fat sat in phalangeal chondrosarcoma. CT, computed tomography; PD, proton density.

Discussion

The role of imaging in bone and soft tissue tumours is clearly established in radiological literature (4,5), but in clinical practice it may be influenced by clinical preferences and technical availability, mostly in regions like the hand, where the majority of lesions are supposed to be benign (6). Preoperative diagnosis must rely on history, physical exam, and imaging techniques.

Clinical accuracy for specific tumour type has been reported to be around 25.6–52% for superficial soft tissue tumours (8) and 47% for deep soft tissue tumours (9). Regarding tumours located at the hand, some clinicians advocate that clinical diagnosis of soft tissue masses may be as high as that reported by imaging methods, around 56% in all cases and 73–96.6% in ganglion cysts, and 50–81.2% for giant cell tumours of tendon sheath (6,10). The figures in the whole sample are lower in our study (32.3%), in which a great variety of bone and soft tissue tumours were present, although very similar in ganglion cyst diagnostic accuracy (72.4%). Nevertheless, we must consider that this is a retrospective study and clinicians were not forced to make a tentative diagnosis before imaging or biopsy results. This might have lowered the accuracy of clinical diagnosis.

The reported accuracy of ultrasound in determining the specific diagnosis for superficial soft tissue masses range from 79–84% (8,11-13) and 58–88% for deep lesions (9,14). With regard to hand lesions, accuracy for soft tissue tumours diagnosis by ultrasound has been reported at around 58% of the cases (6), which is inferior to our study that showed accuracy of 69.8%, but in the range of the general accuracy of ultrasound for soft tissue masses. Regarding ganglion cysts, the reported ultrasound accuracy ranges between 39–87% (6,15), inferior to our results with 100% accuracy. Moreover, this technique allowed us to treat most of them in the same session.

Regarding MRI, the accuracy for soft tissue masses of the hand ranges from 65–94% (6,16-18), which is consistent with our findings. Similarly, the reported accuracy for ganglion cysts ranges from 62.5–100% for MRI (6,10,17,19), also consistent with our results, showing an accuracy of 100% for MRI.

Other common tumours of the hand can also be characterized using imaging methods. Regarding pigmented villonodular synovitis or giant cell tumour of the tendon sheath, 14 cases were included in our series, with correct diagnosis achieved clinically in 7.1%, 62.5% in US, and 100% on MRI. These findings suggest that MRI is the best technique for characterizing these soft tissue tumours, in agreement with the high sensitivity and specificity values reported in the literature (18).

In our 18 vascular tumours, the accuracy obtained was 22.2% for clinical, 61.5% for ultrasound, and 64.3% for MRI, in the range of previous works (18). Five of the vascular tumours were glomus, with clinical versus MRI accuracy of 40% and 100%, respectively. Of note, the MRI accuracy obtained in our study was higher than previous reports (20). Finally, the accuracy values in our 7 neurogenic tumours were 14.3% for clinical, 57.1% for ultrasound, and 75% for MRI, in agreement with previous studies (21).

Our work also demonstrates that imaging techniques are highly accurate in identifying benign soft tissue masses, but figures are much lower in malignant soft tissue tumours. These figures coincide with the literature regarding benign tumours, ranging from 56% to 80% (22,23). Nevertheless, our figures are much lower in diagnosing malignant soft tissue tumours than that reported in the literature (45.2–94%) (8,12,24). This may be due to the variability of institutions where imaging was performed in our study, with great variability of imaging protocols and radiologists experience.

Overall, MRI accuracy is slightly superior to US in most of the soft tissue tumours, but we recommend the latter as the first step because it may rule out pseudotumours (tenosynovitis, accessory muscles, bone overgrowth, pseudoaneurysm, foreign bodies, calcifications, etc.) or diagnose and treat a ganglion cyst, precluding the need for MRI, which is more expensive, less available and may be contraindicated for some patients (25). In non-cystic masses, MRI was superior to US in tissue characterization and accuracy analysis, thus it should be mandatory in decision making planning.

When uncertainty remains about the final diagnosis, including solid or complex cystic lesions, such as myxoma or epidermal cysts, biopsy may provide a definitive preoperative diagnosis. Our work demonstrated high accuracy of core biopsy (86.4%), consistent with a previous report (26). FNs occurred in two malignant postsurgical cases and in one heterogeneous benign tumour with insufficient sample. In another two cases, although there were tumour cells, the final diagnosis differed from the surgical pathology results.

Regarding bone tumours of the hand, most of them are benign and of cartilaginous origin. Most of the revised articles refer to the overlapping characteristic of bone lesions that may preclude an accurate preoperative diagnosis (27). Our figures are high for radiography (84.6%), CT (92.3%) and MRI (90.7%), indicating that imaging provides clues for preoperative high accuracy. When uncertainty remains about the final diagnosis, biopsy may provide a definitive preoperative diagnosis. Differentiating between malignant and benign lesions is important in surgical planning and postoperative management. This is especially important in differentiating enchondroma from chondrosarcoma because due to the small size of the hand bones, scalloping and cortical expansion may be present in both types of lesions (28).

Finally, our work stresses the importance of performing percutaneous needle biopsy under imaging guidance. Its reported accuracy is higher than non-imaging guided biopsies (29,30), with only 8–10% of the procedures being nondiagnostic when proper techniques are used (31,32), according to our results. Three of the FNs were 2 recurrent malignant tumours and a heterogeneous benign lipomatous tumour. Notably, tumour recurrence and lipomatous tumours are considered factors that may reduce the diagnostic yield in percutaneous biopsies (33).

The main limitation of the present work lies in its retrospective nature, but data collection was obtained from official and mandatory clinical sources. Also, the referring doctors belong to different hospitals of three provinces with varying degrees of experience. Imaging methods and protocols were not uniform, neither the experience nor specialization of the reporting radiologists.

This study emerged as an effort of the multidisciplinary oncologic board to raise awareness about not trivializing masses of the hand and wrist despite being mostly benign and stresses the need of following the clinical guidelines (4,5).

Conclusions

In addition to reporting a possible diagnosis, imaging methods help to elucidate the anatomy of the lesions and surrounding structures. In case of non-specific findings, patients should be referred for specialized assessment. Imaging guided biopsy should be preferred over surgical removal in non-specific tumours.

Acknowledgments

The preliminary results of this work were presented as an oral communication in the European Congress of Radiology (ECR 2020). The authors would like to thank 3D Translation SL for their help in revising the English version of the manuscript.

Funding: None.

Footnote

Provenance and Peer Review: With the arrangement by the Guest Editors and the editorial office, this article has been reviewed by external peers.

Reporting Checklist: The authors have completed the STARD reporting checklist. Available at: https://qims.amegroups.com/article/view/10.21037/qims-24-347/rc

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-347/coif). The special issue “Advances in Diagnostic Musculoskeletal Imaging and Image-guided Therapy” was commissioned by the editorial office without any funding or sponsorship. F.R.S. served as the unpaid Guest Editor of the issue and serves as an unpaid editorial board member of Quantitative Imaging in Medicine and Surgery. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). This study was approved by the Provincial Ethics Committee of Granada (approval code: TFG-EITM-2020) for reviewing medical records. Individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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