554 J Clin Pathol 2000;53:554–557 Oesophageal rhabdomyoma J Clin Pathol: first published as 10.1136/jcp.53.7.554 on 1 July 2000. Downloaded from

F Roberts, A J B Kirk, I A R More, J Butler, R P Reid

Abstract Extracardiac rhabdomyomas are rare benign tumours showing striated muscle diVerentiation. Seventy percent of these lesions occur in the head and neck region. The most common sites for these lesions are the larynx, pharynx, and the floor of the mouth. There has been only one previous report of a rhabdomyoma of the oesophagus; two further cases are described. (J Clin Pathol 2000;53:554–557)

Keywords: rhabdomyoma; oesophagus

Extracardiac rhabdomyoma is a benign tumour showing striated muscle diVerentiation. It is distinct from cardiac rhabdomyoma, which is considered to be a hamartomatous lesion often associated with tuberous sclerosis.1 Extracar- diac rhabdomyomas are rare tumours. Three subtypes are generally recognised: fetal, genital, and adult rhabdomyoma.2 Fetal rhabdomyoma occurs primarily in the subcutaneous tissues of the head and neck of male infants usually less than 3 years of age. Genital rhabdomyomas are slow growing lesions in the vagina or vulva of

young or middle aged women. Adult rhab- http://jcp.bmj.com/ domyomas occur at a mean age of approxi- mately 50 years although there is a wide age range.2 They have a predilection for the head and neck region. Some authors also include rhabdomyomatous mesenchymal hamartoma as a fourth subtype of rhabdomyoma.3 This is an unusual lesion that occurs principally on the face and neck of infants and young children. It on September 28, 2021 by guest. Protected copyright. consists of striated muscle bundles inter- Department of spersed with islands of adipose tissue, fibrous Pathology, Victoria tissue, and occasionally proliferated nerves.3 Figure 1 Barium swallow showing a well circumscribed Infirmary, Langside filling defect in the mid-oesophagus. Road, Glasgow There has been only one previous report of a G42 9TY, UK rhabdomyoma of the oesophagus, which was of lobulated lesion was identified within the wall of 4 F Roberts adult subtype. This lesion occurred in the the middle third of the oesophagus. A longitudi- upper thoracic oesophagus of an 8 year old boy. nal myotomy was made over the lesion, which Department of Histological examination revealed a well en- was then excised. The postoperative period was Pathology, Western capsulated tumour composed of randomly ori- Infirmary, Dumbarton uneventful and the patient was discharged Road, Glasgow entated muscle fibres with numerous cross home. Six weeks later she had made a full recov- G11 6NT, UK striations. We present two further cases of ery and her symptoms of dysphagia had I A R More rhabdomyoma of the oesophagus. The clinical, completely resolved. R P Reid histological, and electron microscopic features of this rare lesion are described and the diVer- Pathological findings Department of ential diagnosis discussed. Cardiothoracic The surgical specimen comprised a partially Surgery, Western encapsulated firm white mass measuring Infirmary Case reports 90 × 35 × 5 mm. The cut surface displayed a A J Kirk CASE 1 whorled pattern. Histological examination of J Butler A 21 year old woman presented with a two year the lesion showed a tumour composed of inter- Correspondence to: history of dysphagia. Barium swallow showed a lacing fascicles of spindle shaped cells. Inter- Dr F Roberts filling defect in the oesophagus (fig 1). Com- spersed between the spindle cells there were email: [email protected] puted tomography (CT) scanning suggested large ovoid cells with copious eosinophilic Accepted for publication that the oesophagus was being compressed by an cytoplasm (fig 2A). Phosphotungstic acid hae- 4 November 1999 extrinsic lesion. Subsequently, at surgery, a firm matoxylin showed clear cross striations in many Short report 555 J Clin Pathol: first published as 10.1136/jcp.53.7.554 on 1 July 2000. Downloaded from

Figure 2 (A) Some areas contain large ovoid cells with copious eosinophilic cytoplasm (arrows) (haematoxylin and eosin). (B) Cross striations (arrows) within the spindle shaped cells (phosphotungstic acid haematoxylin). of the spindle shaped cells. Immunohisto- chemical staining for muscle specific actin (Lipshaw, Pittsburgh, Pennsylvania, USA) and desmin (Lipshaw) was strongly positive. Cyto- genetic analysis of the tumour revealed a normal female karyotype. Electron microscopy performed on glutaraldehyde fixed material showed spindle shaped cells containing alter- nating thick (myosin) and thin (actin) myofila-

ments (fig 3). There was focal condensation of http://jcp.bmj.com/ these thick and thin filaments to form rudi- mentary Z bands (fig 3). Consistent with myo- cyte diVerentiation the tumour cells also contained numerous mitochondria and clus- ters of glycogen particles.

CASE 2 on September 28, 2021 by guest. Protected copyright. A 30 year old man presented with epigastric pain and symptoms of reflux oesophagitis. Endoscopy showed a submucosal mass. This was confirmed on barium meal, which also demonstrated a sliding hiatus hernia. Biopsy of this mass suggested a leiomyoma of the oesophagus. At surgery the lesion was identi- fied in the distal oesophagus. This could not be Figure 3 Electron microscopy shows focal condensation of reached with a rigid oesophagoscope and a left thick (large arrowhead) and thin (small arrowhead) lateral thoracotomy was therefore performed. filaments to form rudimentary Z bands. The pleura and muscle were incised and the tumour was freed from the overlying mucosa. The postoperative period was uneventful and ovoid cells with eosinophilic cytoplasm inter- the patient was discharged home after five days. spersed between the spindle cells. Phospho- Six weeks later he had made a full recovery and tungstic acid haematoxylin showed clear cross was discharged from follow up. striations in many of the spindle shaped cells (fig 2B). Immunohistochemical staining for Pathological findings muscle specific actin and desmin was again The surgical specimen consisted of an irregu- strongly positive. Similar to case 1, electron larly shaped firm white tumour received in two microscopy performed on formalin fixed mate- pieces, measuring 55 × 30 × 20 mm and rial showed spindle shaped cells containing 20 × 20 × 6 mm, respectively. Histological ex- alternating thick (myosin) and thin (actin) amination showed a lobulated tumour com- myofilaments. There was focal condensation of posed of spindle shaped cells. Similar to the these thick and thin filaments to form rudi- first case, there were numerous groups of large mentary Z bands. The tumour cells also 556 Short report

contained numerous mitochondria and clus- The diVerential diagnoses for oesophageal ters of glycogen particles. rhabdomyoma include leiomyoma and granu- J Clin Pathol: first published as 10.1136/jcp.53.7.554 on 1 July 2000. Downloaded from lar cell tumour. The initial biopsy in case 2 suggested a leiomyoma of the oesophagus and Discussion this is therefore an important diVerential diag- Extracardiac rhabdomyomas are extremely nosis. Leiomyomas are the most common rare tumours comprising less than 2% of all benign tumours of the oesophagus.14 They neoplasms showing striated muscle diVerentia- usually arise within the muscle layers of the tion. The three commonly recognised sub- distal third of the oesophagus and are easy to types, adult, fetal, and genital, are clinically and “shell out” at surgery. In the two cases morphologically distinct. The most common described, both surgeons commented that the sites for the adult subtype are the larynx, phar- lesion was diYcult to shell out and appeared to ynx, and the floor of the mouth.2 Unusual sites be incorporated into the surrounding tissues. include the orbit,5 stomach,6 mediastinum,7 Microscopically, leiomyomas are composed of prostate,8 and heart.9 They usually present as a interlacing fascicles of spindle shaped cells that slow growing, solitary mass. As in the two cases stain positively for desmin and smooth muscle described, clinical symptoms are often related actin. The large ovoid cells present in adult to obstruction of the aerodigestive tract.2 rhabdomyoma are absent. Electron microscopy Uncommonly these tumours may present with shows numerous cytoplasmic filaments, pino- multiple nodules in the same location.10 cytotic vesicles, and a thick basal lamina,15 but The characteristic histological features of there are no Z bands or alternating thick and adult rhabdomyoma are sheets of large ovoid or thin filaments. 2 polygonal cells with eosinophilic cytoplasm. Striated muscle diVerentiation has been The cytoplasm may be finely granular or vacu- observed occasionally in leiomyomas—for ex- olated owing to the presence of glycogen. ample, within the uterus.16 These authors Cytoplasmic cross striations are usually diY- describe a lesion composed predominantly of cult to identify on routine haematoxylin and spindle shaped cells with blunt ended nuclei. In eosin sections, but can be identified in some some areas there were ribbon like and polygo- cases with a phosphotungstic acid haematoxy- nal cells with abundant eosinophilic cytoplasm. lin. Most cells in adult rhabdomyoma can be These cells stained positively for muscle immunostained with antibodies to muscle spe- specific actin whereas the spindle cells were 11 cific actin, desmin, and myoglobin. Fetal negative. In the two cases described herein, the rhabdomyomas originate in the subcutaneous nuclei of the spindle cells were not characteris- tissues of the head and neck of male infants. tic of a leiomyoma. Furthermore, both the They are composed of a mixture of undiVeren- spindle and ovoid cells stained positively for tiated spindle shaped cells with an indistinct muscle specific actin, and rudimentary Z bands cytoplasm and myoblasts at diVerent stages of were identified within most tumour cells on

2 http://jcp.bmj.com/ diVerentiation. Genital rhabdomyoma is a electron microscopy. submucosal lesion occurring in the vagina or Granular cell tumours of the oesophagus are vulva composed of elongated strap like cells 2 usually situated in the submucosa and are usually with prominent cross striations. associated with pseudoepitheliomatous hyper- Electron microscopy of these lesions shows plasia of the overlying mucosa.17 The two variable numbers of rudimentary myofibrils in 11 12 oesophageal rhabdomyomas described in our the cytoplasm of virtually all of the cells. report were situated within the muscularis pro-

These myofibrils are composed of alternating pria of the oesophagus. Furthermore, granular on September 28, 2021 by guest. Protected copyright. thick (15 nm myosin) and thin (6 nm actin) cell tumours stain positively for S-100 protein myofilaments. Focal condensation of myofi- and are negative for desmin.17 In our two cases, brils forms Z bands. The cytoplasm of the the large ovoid cells were negative for S-100 myocytes contains numerous mitochondria. protein and positive for desmin. These might show a range of abnormalities, the The cell of origin of these tumours is uncer- most common of which is the presence of par- tain, but most probably they arise from primi- allel arrays of cristae containing electron dense 12 tive mesenchymal stem cells that undergo stri- material. Mitochondria were numerous ated muscle diVerentiation, and not from within the tumour cells of the two cases diVerentiated striated muscle tissue. This is described; however, poor fixation precluded analogous to rhabdomyosarcoma, which can assessment of mitochondrial substructure. Z arise in areas in which there is no striated mus- bands and structurally abnormal mitochondria cle, such as the bladder and bile duct.18 The are less prominent in the fetal subtype of 13 recommended treatment for adult rhabdomyo- rhabdomyoma. Variable numbers of glycogen mas is complete excision. Removal of the lesion particles are found within the cytoplasm in 12 resulted in complete resolution of symptoms in most of the tumour cells. the two cases described. Recurrence is rare and The two cases described in this case report is thought to be associated with incomplete fit best with an adult type rhabdomyoma with resection.2 large ovoid cells. In some areas, the lesions were composed of spindle shaped cells but these were much less cellular than a classic fetal 1 Burke AP, Virmani R. Cardiac rhabdomyoma. Mod Pathol 1991;4:70–4. rhabdomyoma. Furthermore, electron micros- 2 Willis J, Abdul-Karim F, di Sant’Agnese PA. Extracardiac copy demonstrated numerous rudimentary Z rhabdomyomas. Semin Diagn Pathol 1994;11:15–25. bands, which are usually inconspicuous in a 3 Enzinger FM, Weiss SW. Rhabdomyoma. In: Enzinger FM, Weiss SW, eds. Soft tissue tumours, 3rd ed. St Louis: Mosby, fetal rhabdomyoma. 1995:523–37. Short report 557

4 Pai GK, Pai PK, Kamath SM. Adult rhabdomyoma of the 12 Warner TFCS, Goell W, Sundharades M, et al. Adult rhab- esophagus. J Pediatr Surg 1987;22:991–2. domyoma. Ultrastructure and immunocytochemistry. Arch

5 Knowles DM, Jakobiec FA. Rhabdomyoma of the orbit. Am Pathol Lab Med 1981;105:608–11. J Clin Pathol: first published as 10.1136/jcp.53.7.554 on 1 July 2000. Downloaded from J Ophthalmol 1975;80:1011–18. 13 Konrad EA, Meister P, Hubner G. Extracardiac rhab- 6 Tuazon R. Rhabdomyoma of the stomach. Report of a case. domyoma. Report of diVerent types with light microscopic Am J Clin Pathol 1968;52:37–41. and ultrastructural studies. Cancer 1982;49:898–907. 7 Miller R, Kurtz SM, Powers JM. Mediastinal rhab- 14 Solomon MP, Rosenblum H, Rosato FE. Leiomyoma of the domyoma. Cancer 1978;42:1983–8. esophagus. Ann Surg 1984;199:246–8. 8 Morra MN, Manson AL, Gavrell GJ. Rhabdomyoma of 15 Mackay B, Ro J, Floyd C, et al. Ultrastructural observations prostate. Urology 1992;29:271–3. in smooth muscle tumors. Ultrastruct Pathol 1987;11:593– 9 Yu GH, Kussmaul WG, diSesa VJ, et al. Adult intracardiac 607. rhabdomyoma resembling the extracardiac variant. Hum 16 Fornelli A, Pasquinelli G, Eusebi V. Leiomyoma of the Pathol 1993;24:448–51. uterus showing skeletal muscle diVerentiation: a case 10 Kapadia SB, Meis JM, Frisman DM, et al. Adult report. Hum Pathol 1999;30:356–9. rhabdomyoma of the head and neck. A clinicopathologic 17 de S Coutinho DS, Soga J, Yoshikawa T, et al. Granular cell and immunophenotypic study. Hum Pathol 1993;24:608– tumors of the esophagus. A report of two cases and review 17. of the literature. Am J Gastroenterol 1985;80:758–62. 11 Helliwell TR, Sisson MCJ, Stoney PJ, et al. Immunohisto- 18 Enzinger FM, Weiss SW. Rhabdomyosarcoma. In: Enzinger chemistry and electron microscopy of head and neck rhab- FM, Weiss SW, eds. Soft tissue tumours, 3rd ed. St Louis: domyoma. J Clin Pathol 1988;41:1058–63. Mosby, 1995:539–77.

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