Benign mesenchymoma of the oral soft tissues

Benign mesenchymoma of the oral soft tissues

Benign mesenchymoma of the oral soft tissues Paul D. Freedman, D.D.S., * M. D. Chou, D.D.S., ** Harold Diner, D.D.S., ** and Harry Lumerman, D.D.S.,* ...

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Benign mesenchymoma of the oral soft tissues Paul D. Freedman, D.D.S., * M. D. Chou, D.D.S., ** Harold Diner, D.D.S., ** and Harry Lumerman, D.D.S.,* Flushing and Bronx, N. Y. BOOTH MEMORIAL MEDICAL CENTER AND ALBERT EINSTEIN COLLEGE OF MEDICINE Benign mesenchymoma is a mixed tumor of mesenchymal derivatives. These tumors are composed of an admixture of two or more benign mesenchymal components in addition to fibrous tissue. A case of benign mesenchymoma of the base of the tongue in a 2%year-old girl is presented. The literature is reviewed and discussed.


he term mesenchymoma was introduced by Klein4 in 1932 to describe a primitive malignant mesenchymal neoplasm that showed marked histologic similarity to Ewing’s sarcoma. Stout,9 in 1948, was the first to use the term mesenchymoma in the sense in which it is now understood, that of a mixed tumor of identifiable mesenchymal derivatives. He described benign and malignant forms and observed that most of these tumors occurred in the urogenital tract. In 1962, LeBer and Stout6 clearly defined benign mesenchymoma as a tumor composed of an admixture of two or more mature mesenchymal components in addition to fibrous connective tissue. We present here a case which fulfills these criteria and exemplifies the difficulties of diagnosis of this unusual lesion. CASE REPORT

A 2%year-old girl presentedwith a massin the baseof the tonguenear the midline (Fig. 1). Previoushistory was unremarkable. The growth had been present for an unknown period of time and was not painful or tender. The lesion, which measured 2 cm. in diameter, was elevated, with a sessile base, and was firm to palpation. It was covered with a smooth, intact mucosal surface and exhibited prominent vascular markings. The tumor was excised under local anesthesia and submitted for microscopic examination. Examination of the microscopic sections revealed intact stratified squamous epithelium covering an unencapsu*Department of Dentistry, Section of Oral Pathology, Booth Memorial Medical Center. **Division of Dentistry, Rose F. Kennedy Center, Albert Einstein College of Medicine. 606

1. Clinical photograph of a 2 cm. raised massin the base of the tongue near the midline.


lated polypoid tumor. The tumor was composed of a fibrous connective tissue stroma containing an admixture of mature mesenchymal elements. Moderate-sized blood vessels exhibiting muscular walls were noted adjacent to lobules of mature adipose tissue. In addition, numerous fascicles of smooth muscle cells were present (Figs. 2, 3, and 4). The different mesenchymal components were arranged and intermixed in a haphazard fashion. In the deeper portion of the tumor, the smooth muscle fascicles extended between the regional serous gland lobules and

infiltrated into the striated muscleof the tongue (Figs. 5 and 6). The cellular components of the tumor did not 0030-4220/82/060606

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@ 1982 The C. V. Mosby Co.

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Benign mesenchymoma of oral soft tissues


Fig. 2. Photomicrograph of unencapsulated tumor composedof an admixture of fibrous connective tissue, blood vesselsexhibiting muscular walls (upper right corner), mature adipose tissue, and fascicles of smooth muscle (bottom center). (Hematoxylin and eosin stain. Magnification, X 100.)

Fig. 3. Photomicrograph of blood vessels exhibiting muscular wall adjacent to mature adipose tissue. (Hematoxylin and eosin stain. Magnification, X100.)

exhibit anaplastic features, and no mitotic figures were identified. The diagnosis was benign mesenchymoma of the tongue. DISCUSSION

The benign mesenchymoma was described by LeBer and Stout6 as a tumor composed of two or

more mesenchymal elements not ordinarily found together, in addition to fibrous connective tissue. This was not always Stout’9 concept of the neoplasm. Originally he conceived of the benign mesenchymoma as a venous hemangioma with connective tissue metaplasia. The prominent vascular component of these lesions was what led to this conclusion. Eventually he decided that they were actually mixed


Freedman et al.


Oral Xurg. June. 1982

4. Photomicrograph of bundles of smooth muscle cells. (Hematoxylin and eosin stain. Magnification,


mesenchymal tumors with all of the connective tissue elements participating in the growth. In a case like the one presented here, other diagnoses, such as hamartoma or angiomyolipoma, should be considered. Although a mesenchymoma might be considered to be a hamartoma, LeBer and Stout6 did not believe that term accurately describes these tumors. Becauseof the common occurrence of these lesions in the skin and kidney, both areas with large amounts of epithelial elements, true hamartomas of these organs, they thought, should have prominent epithelial components. These features are not seen in mesenchymomas. Similarly, in a mesenchymal hamartoma of the tongue, one would expect to see a prominent striated muscle component. Striated muscle was not present in the substance of our tumor, only at the base near the regional serous glands. Instead, our tumor consisted of an exophytic growth composedof a large amount of fat and smooth muscle (in addition to blood vessels and fibrous connective tissue), two types of tissue not normally found to any extent in the tongue. The presenceof this tissue justifies a diagnosis of benign mesenchymoma as opposed to hamartoma. The term angiomyolipoma. according to LeBer and Stout,6 is just one of a long list of synonyms for benign mesenchymoma. Some of these include capsuloma, fibroblastoma, lipomyohemangioma, fibromyxolipoma, and fibrolipoma. They state that naming each individual tumor by stringing together the names of the different mesenchymal components is

unwieldly and would be simplified if the term mesenchymoma was used to describe all of these lesions. In the series of thirty-nine cases described by LeBer and Stout,6 nine presented in the kidney and perirenal tissue, eight in the lower extremity, and sevenin the upper extremity. Only two casesinvolved the head and neck region. Females were affected twice as frequently as males. Forty-one percent occurred in the first 5 years of life, 56 percent in the first 10 years of life, and approximately 70 percent in the first 15 years of life. All of the tumors were well circumscribed but unencapsulated and always seemedto be minimally infiltrative. They contained varying amounts of fat, blood vessels,smooth muscle, striated muscle, cartilage, myxoid tissue, lymphoid tissue, and hematopoietic tissue. Thirty-six of thirty-nine cases contained fat, and all contained blood vessels. Twenty-five of thirtynine contained smooth muscle, with the other mesenchymal elements being present in small numbers of cases. In our review of the world literature, we were able to identify only eight cases,including ours, of benign mesenchymoma of the oral soft tissues.‘*2,3*5,‘t8 Five, including our cases, occurred in the tongue, two in the floor of the mouth, and one in the palate. Six of the eight patients were males. The age range was 7 months to 69 years. Four of the eight patients were in the first decade of life (Table I).

Volume 53 Number 6

Benign mesenchymoma of oral soft tissues

Fig. 5. Photomicrograph of smooth muscle bundles “infiltrating” lobules. (Hematoxylin and eosin stain. Magnification, X 100.)


close to regional minor salivary gland

Fig. 6. Photomicrograph of smooth muscle (left side of field) infiltrating skeletal muscle (right side of field). (Hematoxylin and eosin stain. Magnification, x450.)

No lesion was smaller than 2 cm., most were 3 to 4 cm. in diameter, and two were described as “large.” Six of the eight oral tumors contained a prominent vascular component, seven contained fat, four contained myxoid tissue, three smooth muscle, three skeletal muscle, three cartilage, and two bone.

Our tumor was composedof an admixture of blood vessels exhibiting muscular walls, adipose tissue, fibrous tissue, and numerous bundles of smooth

muscle. The tumor was unencapsulated and showed extension of the smooth muscle component between lobules of minor salivary glands and into the regional skeletal muscle of the tongue (Fig. 5).

610 Freedman et al. Table

Oral Surg. June, 1982

I Authors




Pathologic features


Micheau et al.’

I mo


Lavoie et als

9 yr.




Cracovaner and Vieta’

3 yr.


Base of tongue


Hatziotis et al2

23 yr.

Januska et al.’

69 yr.

Dorsal midtongue Floor of mouth

Size of “small walnut” 2.5 cm

38 yr.

Floor of mouth

4.0 cm

Nishijima et al.*

52 yr.



Freedman et al. (present case)

2% yr.

Base of tongue



Base of tongue


Although our tumor appeared infiltrative, this is consistent with almost all of the previously described benign mesenchymomas and does not in itself connote malignancy. In addition to infiltration, one would need to see anaplasia of the cells comprising the connective tissue component of the tumor to consider a malignant diagnosis. There have been no reported recurrences of benign mesenchymoma of the head and neck, but the follow-up times have been short. In their analysis of the literature on the subject, Januska and coworkers3 suggested that the primary treatment for lesions of the oral cavity should be local excision. This was basedon the lack of reported recurrences of tumors from this region. They also found that in sites other than the oral cavity, when there is a recurrence of a benign mesenchymoma, it most often is as a malignant tumor. They concluded, therefore, that any recurrence should be treated aggressively. Clearly, additional reports of benign mesenchymoma of the oral soft tissues with long-term followup are needed to determine proper treatment and prognosis of these lesions. REFERENCES

1. Cracovaner, A. J., and Vieta, J. 0.: Benign Mesenchymoma of the Tongue, Arch. Otolaryngol. 89: 665-668, 1969.

Fibrous tissue, cartilage, myxoid tissue Fibrous tissue, myxoid tissue, blood vessels, striated muscle, smooth muscle Fibrous tissue, fat, cartilage, smooth and striated muscle, myxoid tissue blood vessels, lymphoid tissue Fibrous tissue, fat, bone, striated muscle Fibrous tissue, fat, blood vessels Fibrous tissue, fat, blood vessels Fibrous tissue, fat blood vessels,myxoid tissue, cartilage, bone Fibrous tissue, fat, blood vessels,smooth muscle









Wide excision

















2. Hatziotis, J. C., Papanayotou, P. ‘H., and Trigonidis, G.: Benign Mesenchymomas of the Tongue: Report of a Case, J. Oral Surg. 30: 45-46, 1972. 3. Januska, J., Leban, S. G., and Mashberg, A.: Mesenchymoma: A Review of the Literature and Report of Two Cases, J. Surg. Oncol. 8: 229-236, 1976. Klein, W.: Mesenchymoma, J. Med. Sot. N.J. 29: 774-778, 1932. Lavoie, R., Lavoie, J., and Belisle, 6.: Mbenchymome Benin de la Langue, L’Union Mid. Canada 97: 744-745, 1968. LeBer, M. S., and Stout, A. P.: Benign Mesenchymomas in Children, Cancer 15: 598-605, 1962. Micheau, C., Gerard-Marchan;, R., and Cachin, Y.: Les Tumeurs Rares De La Langue Etude Anatomo-Pathologique 1t6ropos de I78 cas), Arch. Anat. Pathol. 16: 119-128, 8. Nishijima, K., Nagahata, S., Okamoto, Y., Ishida, M., Matsumura, K., Tohdoh, M., and Baba, M.: A Case of Mesenchymoma in the Oral Cavity Clinically Resembling a Large Pleomorphic Adenoma, Acta Med. Okayama 33: 53-60, 1979. 9. Stout, A. P.: Mesenchymoma, the Mixed Tumor of Mesenchymal Derivatives, Ann. Surg. 127: 278-290, 1948. Reprint requests to:

Dr. Paul D. Freedman Assistant Director Oral Pathology Laboratory, Inc. Booth Memorial Medical Center 56-45 Main St. Flushing, N. Y. 11355