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What is the diagnosis?
¿Cuál es su diagnóstico?

 

Male patient, 64 years old, with a history of arterial hypertension, having a duodenal ulcer for some time. He had been operated for appendicitis with peritonitis, had varicose veins in the lower extremities, and had been referred to us by the anesthetist on observing during oral examination a tumor-like growth in the tongue. This had not been noticed by the patient who was unable to say how long he had had it for. It was painless and there was no additional regional or general clinical [observations].

During the intraoral examination, a tumor-like growth was observed on the edge of the right side of the tongue which was round, submucosal, nonulcerated, yellowish in color, hard and with a diameter of approximately 2 cm (Fig. 1). It was painless and there was no loss of sensitivity in the area. The submaxillary glands and the floor of the mouth were normal. Cervical adenopathies were not observed.

An excisional biopsy was decided upon using a CO₂ laser in a continuous mode with a strength of 10 watts (Fig. 2), as it appeared to be a benign tumor of soft tissues and there was a lack of clinical [symptoms] and conclusive data. Complete enucleation of the tumor was achieved, the muscle bed was then widely vaporized using 10 watts, and suturing was not necessary (Fig. 3)

 

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Lingual liposarcoma
Liposarcoma lingual

 

V. Ordóñez¹, A. González¹, J. Giner¹, L. Maniegas¹, R. Martín-Granizo²

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1 Médico Residente
2 Médico Adjunto
Servicio de Cirugía Oral y Maxilofacial (Jefe de Servicio: Dr. a. Berguer)
Hospital Clínico San Carlos. Madrid, España

Correspondencia:
Dr. Rafael Martín-Granizo López
Servicio de Cirugía Oral y Maxilofacial. Hospital Clínico San Carlos
C/ Profesor Martín Lagos s/n. 28040 Madrid
e-mail: rmartín.hcsc@salud.madrid.org.

 

Microscopical analysis revealed the presence of adipocytes of different sizes (Fig. 4), generally well-differentiated, a variable number of lipoblasts (Fig. 5) and some atypia.

The nodule corresponded with a neoplasy of adipocytes, and more precisely with a lipoma-like, well-differentiated liposarcoma.

The lesion was surrounded by a fine layer of connective tissue, which had been completely removed during the surgery. Clinical and radiological following of the patient was later decided upon, and after 6 months there was no evidence of any recurrence.

Discussion

Liposarcoma is currently considered the most common sarcoma of soft tissues, accounting for 20% of all mesenchymal malignant tumors of soft tissues in adults.¹

It is most commonly found on the thighs, buttocks and retroperitoneum.¹ Liposarcomas of the head and neck are infrequent, representing in the different series that have been published, between 5.6 and 9% of the total.^1,2 Intraoral liposarcomas are extremely rare representing 10% of those of the head and neck.³

Those located in the head and neck which have been published in the literature are: scalp (12 cases), larynx (29 cases), hypopharynx (8 cases), esophagus (6 cases), oral cavity (81 cases), neck (22 cases) and orbit (26 cases).^4-6

Within the oral cavity the most frequent locations differ from one published series to another (Table 1).

Liposarcoma appears more frequently in males,^5,7 the age range being between 28 and 83 years (median 49.5 years).⁵ In most patients the tumor is diagnosed after the fifth decade of life.⁵

Although the specific etiology of liposarcoma is unknown, its association with trauma and the resulting hematoma, approximately a year before the development of the tumor, has been published.^{5, 8}

In the case we are reporting there could be a connection, as the location in a free part of the tongue towards the back, could have been related to friction from biting.

In the majority of the studies published, the oral liposarcoma evolves as a slow growing, painless mass.

The most important marker in clinical behavior and prognosis of liposarcoma is the histological subtype.⁷

The current histopathological classification of liposarcoma by the WHO (1994)⁹, distinguishes 5 variants (Table 2) which do not differ too much from the proposals of Enzinger and Winslow, 8 at the beginning of the 60s, except in a fifth subtype (the undifferentiated liposarcoma).

Histology

The series published more recently show a clear predominance in intraoral location of the well-differentiated lipomalike histological type (95%).⁵ The lipoma-like subtype is composed of mature adipocytes displaying variations in cellular size and little nuclear atypia.

For a long time, the presence and number of multivacuolated lipoblasts was considered a diagnostic criteria for well-differentiated liposarcoma. However, we now know that the number of lipoblasts can vary from several to none, and that they are not an essential requirement for a diagnosis.¹⁰ On the other hand a considerable number of benign adipocyte tumors have lipoblasts, such as: spindle-cell type lipoma, pleomorphic lipoma, lipoblastoma and chondrolipoma. The well-differentiated liposarcoma is characterized by a risk of local recurrence of 30%, although it is unable to spread unless it becomes undifferentiated.

Cytogenetics

The well-differentiated liposarcoma is characterized by the presence of giant chromosomes and ring chromosomes derived from the long arm of chromosome 12.¹¹ In these chromosomes there is amplification and the subsequent overexpression of genes of the 12q13-15 region,¹² labeled MDM2, CDK4 and SAS, which are related with the tumorigenesis of various bone and soft tissue sarcoma, including liposarcoma.¹²

The MDM2 negative immunophenotype of the lipomas can be used to distinguish between lipoma and well-differentiated lipoma- like liposarcoma.¹¹

Diagnosis

The difficulty in diagnosing liposarcoma using FNAB and even with biopsy, is well documented.⁶ The histology of a well-differentiated liposarcoma can be extremely like that of a lipoma, as lipoblasts may be absent or completely widespread in the tumor. A FNA or a biopsy may not contain these cells. Often complete resection of the mass is therefore necessary for a definitive histopathologic diagnosis (Fig.6).

The radiographic appearance of liposarcomas varies enormously. The well-differentiated type, has a typical homogenous appearance on the CT scan, similar to that of the lipoma, with sharp demarcation from surrounding tissues. Other histological types of liposarcomas have a heterogeneous appearance.¹³

The characteristics of liposarcomas in MRI, have also been published, although precise diagnosis with this modality is still not possible.¹⁴

Recent studies with proton NMR spectroscopy have showed promise regarding the diagnosis of liposarcoma This technique can forecast the histology of the tumor, based on the amount of triglycerides and phosphatidylcholine in the tumor.¹⁵

Differential diagnosis

When a fatty tumor with an intraoral location is examined, one has to take into consideration benign tumors with adipocyte component (hibernoma, angiolipoma, chondrolipoma, fibrolipoma, lipoma, spindle cell lipoma), other benign tumors (myxoma, pleomorphic adenomas) malignant tumors (myxofibrosarcoma, malignant histiocytoma, malignant mesenchyoma), silicone granuloma and fat necrosis.¹ The differential diagnosis is purely histological.

Silicone granulomas are starting to become common due to their frequent use in plastic surgery for silicone lip and cheek implants. They consist in a granulomatose inflammation with vacuoles surrounded by multinucleated giant cells that can mimic lipoblasts.

Treatment

The treatment recommended for liposarcoma is radical extirpation of the tumor, with intraoperative confirmation of free margins.^{3, 7, 13} Simply enucleating the tumor increases the risk of a relapse. Even though on most occasions tumor recurrence is of the same histological type, it can recur as a higher grade tumor. If obtaining clear margins is difficult, due to the membrane of neurovascular structures, some authors consider the use of adjuvant radiotherapy [to be necessary] in order to reduce the probability of local recurrence.¹⁶ Chemotherapy can be efficient in the treatment of tumors that cannot be resectioned or as adjuvant therapy.¹⁶ Ganglionic dissection is not indicated for these tumors, unless there is clear evidence of metastasis which would be extremely unusual.^1,16

Prognosis

Within the different histological types of liposarcoma, well-differentiated and myxoid are low grade, and round cell, undifferentiated and pleomorphic are high grade. The prognosis of liposarcoma is directly related to location and particularly to histological type. Low grade, welldifferentiated and myxoid variants have a better prognosis, with a tendency for local recurrence, but with a small or nonexistent metastasic potential. Round cell, undifferentiated and pleomorphic variants have a worse prognosis, with a higher rate of metastasis and death.

In the different series that have been published, there has been up until now, a marked predominance of low grade liposarcomas. During the following of 76 patients with liposarcomas of the head and neck, 62% were low grade and 38% were high grade.7 In another following of 44 patients with oral liposarcoma, 80% were low grade and 20% were high grade. Long term survival is related more with uncontrolled local recurrence than with metastasic dissemination.

Even though the most important marker in the clinical behavior of liposarcoma is histological type, due to the difficulty in classifying liposarcoma using microscopical criteria, some authors have proposed identifying prognosis markers using molecular and cytogenetical analysis. Several studies have revealed models of molecular change which are very useful for specifying the different types of liposarcoma, as well as for clarifying pathogenesis, proposing a new classification system and determining the prognosis of liposarcoma.

Conclusions

Liposarcoma are very infrequent in the regions of the head and neck and extremely rare in the oral cavity. The most frequent intraoral locations are in the tongue and cheek. Confirmation is through anatomicopathological diagnosis. The principle marker of clinical behavior and prognosis is the histological type. In the oral cavity the most frequent histological type is the well-differentiated (lipoma-like) liposarcoma, which is characterized by high local recurrence (30%), although it has a low or non-existent metastasic potential. The treatment of choice should be radical resection with tumor free margins, in order to reduce the probabilities of recurrence. A long term following of the patient is, nevertheless, necessary.

References

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