Fine needle aspiration of parapharyngeal space adult rhabdomyoma: a case report.

BACKGROUND: Rhabdomyomas are rare benign tumors of striated muscle and include cardiac and extracardiac types. Extracardiac rhabdomyomas are divided in three subtypes (adult, fetal, genital). The adult type is usually found in the head and neck regions of elderly persons. Misinterpretations in initial diagnosis of adult rhabdomyomas on fine needle aspiration have been reported. CASE: A 64-year-old man presented with gurgling and difficulty swallowing for approximately 3 months. Computed tomography and magnetic resonance imaging showed a 5.8-cm solid mass located in the right parapharyngeal space. Fine needle aspiration smears were cellular, showing cohesive clusters of cells with scattered individual cells. Cells had abundant eosinophilic glassy cytoplasm, peripherally placed round nuclei, and prominent nucleoli. Many traversing vessels were noted, but cross-striations were not seen. The cell block demonstrated clusters of cells with abundant eosinophilic granular cytoplasm, some with clear and/or vacuolated cytoplasm, and possible cross-striations. Tumor cells were positive for desmin. The lesion closely resembled normal muscle tissue. Electron microscopy showed many cells containing actin and myosin filaments with Z-band material. CONCLUSION: Correct diagnosis can be achieved with a combination of awareness of the lesion, familiarity with the characteristic cytologic features, and application of appropriate immunohistochemistry markers. Classic electron microscopic findings can support the diagnosis.

Recurrent parapharyngeal rhabdomyoma. Evidence of neoplastic nature of the tumor from cytogenetic study.

A 64-year-old Caucasian male with a left parapharyngeal mass had a past medical history that was significant for excision of a benign rhabdomyoma of the soft palate 30 years previously. Then 25 years ago, the tumor recurred in the palate and retropharyngeal space on the left and was reexcised. Histologic examination of all three excisions showed adult rhabdomyoma. Ultrastructural and histochemical studies of the second excision of this tumor have been published previously. The present study included histologic, ultrastructural, immunohistochemical, and cytogenetic analyses. The histologic and ultrastructural features of the tumor were identical to those reported 25 years ago. Immunohistochemical studies demonstrated that the tumor cells were desmin and myoglobin positive and vimentin negative. Focal positivity for CD56 was also present. Intracellular inclusions in the tumor cells were strongly positive for desmin. Cytogenetic examination of short-term cultures of the tumor cells demonstrated clonal chromosome abnormalities in 60% of metaphases. The majority of cells showed a reciprocal translocation between chromosomes 15 and 17 as the sole abnormality. A minor clone was characterized by abnormalities of the long arm of chromosome 10. The presence of clonal structural chromosome abnormalities in extracardiac adult rhabdomyoma lends strong support to the idea that these rare tumors are true neoplasms rather than hamartomatous or regenerative lesions.

Malignant rhabdoid tumor of the vulva: is distinction from epithelioid sarcoma possible? A pathologic and immunohistochemical study.

Epithelioid sarcoma (ES) and malignant rhabdoid tumor (MRT) have heretofore been regarded as two separate clinicopathologic entities. However, they have some histologic similarities, and both represent histogenetic and phenotypic enigmas. This study reports the pathologic and immunohistochemical findings of four vulvar neoplasms occurring in young women that represented diagnostic dilemmas because of their similarity to both ES and MRT. Only one case had the classic histologic features of ES, whereas, in our opinion, the other three cases fulfilled the histologic criteria of MRT, despite the fact that two of the three cases were reported earlier as examples of ES. Neither electron microscopy nor immunohistochemistry has been found to be helpful in separating ES from MRT, mainly because they share several ultrastructural and immunophenotypic features. The behavior of these vulvar tumors--ours and the few published examples of ES--is generally aggressive, more in keeping with MRT than classic ES. We believe that some, if not most, putative ES of the vulva are in fact MRT, a neoplasm with an unfavorable prognosis.

Multifocal rhabdomyoma of the neck. Report of a case studied by fine-needle aspiration, light and electron microscopy, histochemistry, and immunohistochemistry.

A 32-year-old Caucasian man presented with a tumor in the right side of the neck. Preoperative fine-needle aspiration showed large multinucleated cells with abundant granular cytoplasm that were consonant with the features of a granular cell tumor. At surgery, two separate tumors were found. Histologically, the tumor proved to be an adult rhabdomyoma, the 11th such multifocal case reported. The striated muscle origin of this benign tumor was confirmed by immunohistochemical and ultrastructural studies. The tumor cells were desmin-, myoglobin-, and actin-positive. They showed variable numbers of thick and thin filaments, as well as hypertrophic Z-band material. Histochemical studies showed the presence of basophilic muscle cells, vesicular nuclei, ragged red fibers, and diffuse acid phosphatase positivity. These features, together with the absence of actual muscle cell proliferation and the assumption that the mass of the tumor could be explained by the enormous swelling of the muscle cells, lead us to conclude that an adult rhabodomyoma is merely the result of a process of disorderly degeneration and regeneration rather than a real neoplasm or a hamartomatous lesion.

Ultrastructure of a cardiac rhabdomyoma.

Electron microscopic study of a cardiac rhabdomyoma removed at open heart operation revealed large rounded or polygonal cells that contained large amounts of monoparticulate glycogen. Myofibrils in these cells were few and located either subjacent to the plasma membranes or radiating from central areas. Leptofibrils and masses of anomalous Z band material were abundant. Shallow tubular sarcolemmal invaginations and elements of free and junctional sarcoplasmic reticulum were associated with the myofibrils. Desmosomes and nexuses were evident in intercellular junctions, which were extensive and randomly distributed throughout the cell surfaces. It is concluded that cardiac rhabdomyomas probably are hamartomas.

Primary cardiac tumors in children.

Case histories of five children with primary cardiac tumors are presented. The clinical and pathological features of the most frequent cardiac neoplasms in childhood are also reviewed. Cardiac tumors should be suspected in any child with unexplained heart murmurs, congestive heart failure, or cardiac arrhythmias. Echocardiography, cardiac catheterization, and biplane cineangiograms provide diagnostic confirmation. Prompt surgical resection is indicated in all symptomatic patients and in those with significant inflow and outflow tumor-related obstruction. Complete resection is not possible in many patients with cardiac rhabdomyoma or lipoma but removal of the obstructive portion of the tumor frequently provides long-term symptomatic relief.

Rhabdomyoma of the soft palate. Fine structural details of a highly differentiated muscle tumor.

An adult rhabdomyoma was light and electron microscopically studied. The lesional cells presented well-known structural details, such as abundance of mitochondria and glycogen, myofilaments and myofibrils, hypertrophied Z-bands and masses of Z-band material. Triads were randomly scattered in the cytoplasm and also related to the individual sarcomeres. In sarcomeres the triads were regularly placed near to the A-I-junctions. This peculiarity of mammalian skeletal muscle fibers may yield a criterion to distinguish between cardiac and extracardiac rhabdomyomas. Circumscribed surface areas of the tumor cells were provided with elaborate infoldings of plasma membrane and basal lamina. These areas were interpreted as imitating myotendinous junctions. Satellite cells were regularly found.

Immunochemistry and electron microscopy of head and neck rhabdomyoma.

Rhabdomyomas are rare benign tumours originating in skeletal or cardiac muscle. Extracardiac tumours are usually situated in the head and neck. Four cases are presented, three arising in the larynx and the other in the cervical region. All four cases were studied by light and electron microscopy, and in three immunohistochemical staining for myoglobin, desmin, and vimentin was carried out to study the diagnostic features of the lesions and their histogenesis.

Benign vaginal rhabdomyoma.

A case of benign polypoid vaginal rhabdomyoma occurring in a 52-year-old female is described. The characteristic histological features were interlacing bands of striated muscle cells with prominent cross and longitudinal striations, with surrounding loose collagenous stroma, within which were many dilated vascular spaces. Electron microscopy confirmed the striated muscle origin of these cells. The pathogenesis is possibly a localized area of abnormal mesenchymal differentiation.

Nasopharyngeal rhabdomyoma. Report of case (light and electron microscopic studies) and review of the literature.

Rhabdomyoma is an extremely rare benign tumor originating from the skeletal or cardiac muscle cells. Only 87 cases of rhabdomyoma have been reported to date, 70% occurring in the head and neck areas. The authors present the fourth case of rhabdomyoma of the nasopharynx. The tumor appeared in an 18 year old woman with hypacusis. Examination of the epipharynx showed a 2 x 1,5 cm tumor, extending from torus tubarius down to the soft palate. Light microscopy disclosed areas and islands of polymorphous large cells with abundant eosinophilic cytoplasm. Cross striations were focally visible with special PTAH staining. Electron microscopy revealed parallel and haphazardly arranged fibrillar bands (myofibrils) with irregularly and periodically arranged densities corresponding to Z lines. The pecularities of our case were abundant cystically dilated rough endoplasmatic reticulum and the absence of cytoplasmatic glycogen.

Adult rhabdomyoma: ultrastructure and immunocytochemistry.

Adult rhabdomyoma is a benign, highly differentiated tumor of skeletal muscle. We observed transverse tubules and triads beside myofilaments in a rhabdomyoma from the submandibular area of a 66-year-old woman. Several types of muscle cells were present. In one, mitochondria abounded; in another, muscle filaments predominated. Myoglobin was also detected in the tumor.

Juvenile rhabdomyoma. An intermediate form of skeletal muscle tumor in children.

Two tumors of the buccal soft tissues in children with rhabdomyomatous features are described and further characterized by immunohistochemical studies in both cases and by electron microscopy in one case. Discrete microscopic nodules of elongated, uniform spindle cells with readily identifiable cytoplasmic cross striations replaced existing normal skeletal muscle. In contrast to fetal rhabdomyoma and embryonal rhabdomyosarcoma, there were no immature mesenchymal cells, nor were there individual rhabdomyomatous cells with short, tapered cytoplasmic processes and overtly malignant cytologic features, including mitotic activity. Following excision, one child remains well 46 months later and the other is doing well 7 months after surgery. Some confusion has been created in the literature by the introduction of the terms cellular rhabdomyoma and myxoid fetal rhabdomyoma. We propose that the so-called cellular fetal rhabdomyoma is distinct from the classic fetal rhabdomyoma and may represent the more differentiated juvenile rhabdomyoma.

Nucleolar organizer regions in normal skeletal muscle and benign and malignant rhabdomyoblastic tumors.

The silver staining of interphase nucleolar organizer regions (NORs) has been shown to have an important application in diagnostic histopathology for distinguishing some benign from malignant conditions. In this study, normal fetal and adult skeletal muscles and tissue from fetal and adult rhabdomyomas as well as rhabdomyosarcomas were stained with the silver method for NORs. The morphologic distribution of NORs in rhabdomyosarcomas was found to be very different from that in normal skeletal muscles. In addition, cases of rhabdomyoma were easily differentiated from rhabdomyosarcomas. Statistical analysis of data, from all cases, regarding the diameter of NORs and number per nucleus confirmed these observations.

Rhabdomyoma of the larynx: a review of the literature with a summary of previously described cases of rhabdomyoma of the larynx and a report of a new case.

A review of extracardial rhabdomyomas of the larynx reported in the literature is presented. A new case is added (the largest described yet). The diagnosis was based on routine histological and immunohistological staining, and electron microscopy. The extracardial rhabdomyomas were divided into three types according to histopathological findings: (i) adult; (ii) foetal cellular type; and (iii) foetal myxoid. There are 23 well-documented cases (including this case) of extracardial rhabdomyomas of the larynx; 15 of the adult type, four of the foetal myxoid type and four of the foetal cellular type. The differential diagnosis and the requisite diagnostic procedure is discussed. The tumour is benign. The treatment is surgical excision. Although rare, its existence should be kept in mind in the differential diagnosis of laryngeal tumours.

Rhabdomyoma of the base of the tongue.

The histopathological and imaging findings of a rhabdomyoma of the base of the tongue were studied. An immunohistochemical examination of the tumour cells showed positive immunostaining for myoglobin, desmin, and striated muscle actin, but negative immunostaining for smooth muscle actin. Electron microscopy showed many glycogen granules and mitochondria in the tumour cells. The T2-weighted and contrast-enhanced magnetic resonance images (MRI) clearly delineated morphological features of this tumour, but T1-weighted MRI and computed tomography (CT) images showed no important features. These findings are typical for an adult extracardiac rhabdomyoma located in the head and neck region, and they will be useful for diagnosis of this tumour.

Ultrastructural changes in medullomyoblastoma. Similarities with foetal rhabdomyoma.

The light and electronmicroscopic changes are described in two cases of medullomyoblastoma, and compared with the changes seen in a case of foetal rhabdomyoma. The medullomyoblastomas in two children aged 8 and 5 years, consisted predominantly of classical type of medulloblastoma cells, along with few to many 'strap cells' or 'myoid cells' which, on closer examination, showed clear cross striations, consistent with muscle fibres or myofibrils. The primitive myoid cells were similar to those encountered in larger numbers in a post-auricular rhabdomyoma, possibly of foetal origin in a 40 day old infant. The four pathogenetic mechanisms i.e. (i) an embryonal stage of myofibrillar differentiation; (ii) a malformative factor; (iii) a teratoid factor on account of the presence of mesenchyme derived striated muscle tissue in the obviously predominant ectodermal medulloblastoma; and (iv) metaplasia of the vascular smooth muscle cells in the medullomyoblastoma, are discussed.

[A rare cause of dysphonia: laryngeal rhabdomyoma]. / Une cause rare de dysphonie: le rhabdomyome laryngé.

The authors report a case of laryngeal rhabdomyoma occurring in a young female adult, revealed by a dysphonia. The review of literature shows that both immunohistochemical and electron microscopy studies have rarely been performed for this benign but infrequent tumour in this localization.

[Extracardiac rhabdomyomas]. / Ekstrakardiale rabdomyomer.

Two cases of extracardial rhabdomyomata are described. One case was discovered incidentally at autopsy while the other was primarily examined by needle aspiration biopsy. As far as the authors are aware, this is the first case to be reported.

[Rhabdomyoma of unusual manifestation]. / Szokatlan manifesztációjú rhabdomyoma.

According to our knowledge in adult pericardial effusion has never been reported to be present in cases of cardiac rhabdomyoma. We present the history of an adult patient with pericardial effusion due to cardiac rhabdomyoma.

[Melanoma with a rhabdopoietic differentiation (ectomesenchymoma)]. / Melanoma s rabdopoéticheskoi differentsirovkoi (éktomezenkhimoma).

This is the first description in Russian literature of histological and electron-microscopic structure of an exophytic skin mesenchymoma with melanocytic and rhabdomyopoietic differentiation. The presence in the tumour of cells-hybrids possessing the two differentiations allows one to suppose a histogenetic link of this tumours with pluripotential cells of neuroectoderm.