Clinical History

A 59-year-old female patient with a slowly growing mass of the left hand.

Imaging Findings

A 59-year-old female patient was referred due to slowly growing mass of the left hand over a period of approximately 2 years. The physical examination showed a soft tissue mass of the thenar region on the left hand, which was unrelated to and easily movable on the neighboring structures. An MRI study was performed on a 1.5 T MR scanner, with SE T1, FSE T2, fat-suppressed FSE T2 sequences on three orthogonal planes.

Discussion

Soft tissue lipomas are the most common mesenchymal tumors, which are homogeneous and clearly marginated, with or without internal septations. They usually appear in the fifth to sixth decades of life, and the males are more affected than the females. They reach a stable size after an initial period of discernible growth. These soft tissue tumors are found most commonly in the subcutaneous regions of the posterior trunk, neck, shoulder, proximal extremities. They lodge in deeper locations such as within the thigh, retroperitoneum, anterior mediastinum, gastointestinal wall, deep soft tissues of the hands and feet less frequently . Histopathologically they are composed of mature fat cells that are uniform in size and shape, they may have fibrous connective tissue as septations. Lipomas of the hand are not common neoplasms. Although ultrasonography, computed tomography can be used for the diagnosis and evaluation of the lipomas, MRI is the imaging method of choice for evaluating the presence and extent of the lipomas, providing excellent anatomic detail and soft tissue contrast. Lipomas are well defined masses, with signal intensity characteristics similar to subcutaneous fat, hyperintense on T1 weighted spin-echo, and moderately intense on T2-weighted fast spin-echo images on MRI. The signal intensity of lipomas is nulled on fat-suppressed T2-weighted fast spin-echo images or STIR images. Low signal intensity septations may be seen within the lesions on all sequences. Lipomas do not show contrast enhancement after IV gadolinium injection. The differential diagnosis of lipomas from certain conditions like ganglion, hemangioma, arteriovenous malformation, giant cell tumor of the tendon sheath in the hand is not difficult with the characteristic MRI findings.

Differential Diagnosis List

Thenar lipoma of the hand

Final Diagnosis

Thenar lipoma of the hand

Liscense

Figures

Figure 1

Figure 2

Medical Imaging Report

Imaging Findings

Based on the provided MRI images, a well-defined, fat-like signal lesion is observed in the soft tissues of the left hand. On T1-weighted images, the lesion appears hyperintense, and it is also hyperintense on T2-weighted images. When using fat suppression sequences (such as STIR or FS T2), the lesion’s signal is significantly reduced or suppressed. A small amount of faint, low-signal septations is visible within the lesion, with no obvious enhancement. The lesion is primarily located in the deeper subcutaneous tissue or beneath the fascia, showing some enlargement in volume but with clear demarcation from surrounding muscles, tendons, and the joint space. No significant bone destruction or invasion of adjacent tendon or ligament structures is observed at this time.

Potential Diagnoses

Lipoma: Given its typical fat signal characteristics—high signal on T1-weighted images, high signal on T2-weighted images, and signal suppression on fat-suppressed sequences—along with the absence of significant enhancement, a lipoma is the primary consideration.
Giant Cell Tumor of the Tendon Sheath: Common in the hand, but it typically shows isointense or slightly low signal on T1-weighted images, may have mixed signal on T2, and often exhibits some degree of enhancement, which does not entirely match the current imaging characteristics.
Ganglion Cyst: Generally presents as a cystic lesion, low signal on T1 and high signal on T2, without distinctive fatty components on fat-suppression sequences, and may show obvious wall enhancement. This differs significantly from the typical fat signal seen here.
Hemangioma or Vascular Malformation: These lesions often appear hyperintense on T2 and may show flow voids or enhancement patterns, differing from a pure fatty lesion.

Final Diagnosis

Considering the patient’s age (59 years), the slow growth of the lesion in the left hand, and the distinct presentation of fatty components on MRI without obvious enhancement—together with the clinical history and imaging findings—the most likely diagnosis is a lipoma.

Treatment Plan and Rehabilitation

Treatment Strategy:

For slowly growing lipomas with mild symptoms, small size, and no significant functional impairment, observation and follow-up may be sufficient. Regular assessments of the lesion’s size, pain, or functional impact are recommended.
If the lesion is relatively large or causes significant pain, functional issues, or cosmetic concerns, surgical excision may be considered.
Surgery generally involves complete removal of the lipoma and its capsule to reduce recurrence risk. Typically, no special adjuvant treatment is required.

Postoperative Rehabilitation and Exercise Prescription:

Acute Phase (first 2 weeks): Keep the surgical wound clean and avoid early or excessive activity to prevent bleeding or suture dehiscence. Gentle passive finger movements, light fist clinching, and extension exercises can help promote circulation.
Functional Training Phase (2–6 weeks): Begin gradually increasing range-of-motion exercises of the hand and gentle muscle strengthening. Follow the FITT-VP principles:
- Frequency: 3–4 times per week
- Intensity: Light to moderate resistance (e.g., elastic bands, soft grip balls)
- Time: 10–15 minutes each session, in intervals
- Type: Finger flexion/extension exercises, fist clinching and finger extension, joint flexibility training
- Progression: As pain and swelling diminish, gradually increase resistance or repetitions
Strengthening Phase (after 6 weeks): If hand function recovers well, progress to higher-intensity repetitive grip and pinch training, as well as fine motor activities (e.g., playing piano, grasping small objects) to fully restore hand dexterity and strength.
Individualization Principle: If the patient has other chronic conditions (e.g., osteoporosis, diabetes) or reduced cardiopulmonary function, adjust the exercise intensity and frequency under professional guidance to avoid overexertion or accidental injury.

Disclaimer:

This report is intended for reference only and does not replace in-person consultations or professional medical advice. If you have any questions or if your condition changes, please seek medical attention promptly.

Human Doctor Final Diagnosis

Thenar lipoma of the hand

AI Doctor

Subcutaneous lipoma of the hand

Clinical History