Rhabdomyoma of the head and neck: morphology and differential diagnosis

Fetal rhabdomyoma in a Thoroughbred filly

A newborn Thoroughbred filly presented with a large mass located on the ventro-rostral aspect of the mandible. The mass was surgically removed under general anaesthesia. Upon gross examination, the mass was well circumscribed with a heterogeneous lobulated appearance. The results of histopathology and immunohistochemistry were consistent with a diagnosis of congenital fetal rhabdomyoma. On follow-up at six months post-surgical excision, no abnormalities were noted on clinical examination.

Fetal-Type Rhabdomyoma of the Cheek: A Conservative Management

Extracardiac rhabdomyomas are rare benign mesenchymal tumors diagnosed upon radiological and hystologic investigations and the treatment of choice is surgical exertion. There aren't any similar cases managed conservatively reported in literature as in our case, to the best of our knowledge. We present a rare case of fetal cheek rhabdomyoma diagnosed in a healthy 2 months-old boy, with asymptomatic mass over the left masseter. The lesion could not be removed, due to the size and dimensions and the young age of the patient. However, the lesion did not show signs of spreading or progression over a 36 months follow-up. Fetal rhabdomyoma is a benign tumor, often located in the head and neck district, where surgery, especially in very young children, is associated with a high risk of complications and long-term sequelae. Our case report demonstrates the possibility to manage these lesions conservatively in the first years of life with close sonographic and clinical follow-up.

Sporadic right ventricle rhabdomyoma in an adult without tuberous sclerosis

Cardiac rhabdomyoma is a rare benign tumor of the pediatric age group which usually regresses by the age of 2 years. Cardiac rhabdomyoma in adults is still a rarer disease. It is usually associated with tuberous sclerosis. Patients with cardiac rhabdomyoma will usually be asymptomatic and detected incidentally, or in suspicion to the signs and symptoms of tuberous sclerosis. Symptomatic patients present with palpitations or failure to thrive due to obstructive symptoms leading to cardiac failure. The authors present a rare case of right ventricular rhabdomyoma in an adult without tuberous sclerosis treated surgically.

Benign mesenchymal tumours of the tongue: A report of adult-type rhabdomyoma and granular cell tumour with a review of the literature

The cytomorphological features of benign mesenchymal tumours of the tongue have rarely been reported. Herein, we present the cytomorphological features of adult-type rhabdomyoma, which occurred in the tongue of a female patient, and granular cell tumour (GCT), which occurred in the tongue of a male patient; both patients were in their mid-50s. The cytological features of the adult-type rhabdomyoma case included large polygonal to ovoid cells with abundant and granular cytoplasm with predominantly peripherally located, uniform, round to oval nuclei and small nucleoli. Cross-striation and crystalline intracytoplasmic structures were not seen. The cytological features of the GCT case included large cells with abundant granular pale cytoplasm, small round nuclei and small distinct nucleoli. The cytological differential diagnoses of these tumours overlap; thus, the cytological findings of the different entities included in their differential diagnoses are discussed.

Oral Adult Rhabdomyoma

This report describes a case of an adult rhabdomyoma (ARM) occurring in the oral cavity. A 47-year-old man was referred for the diagnosis of a painless, well-circumscribed, submucous nodule located on the floor of the mouth, measuring approximately 6.0 cm in length. Computed tomography revealed a well-defined, solid, and hypodense mass. A benign salivary gland or mesenchymal tumor were the main diagnostic hypotheses. Under local anesthesia, the patient underwent surgical excision. Microscopically, the tumor comprised large polygonal well-defined cells with abundant, eosinophilic granular cytoplasm with cross striations. No atypia or mitosis was observed. The cells were positive for muscle-specific actin, desmin, and sarcomeric alpha-actin. Based on these features, a diagnosis of ARM was established. No recurrence was observed after 48 months. Although rare, ARM should be considered in the differential diagnosis of oral submucosal nodules, especially those located on the floor of the mouth.

The Extremely Rare Hypopharyngeal Fetal Rhabdomyoma in an Adult

Extracardiac rhabdomyomas are rare benign tumors showing skeletal muscle differentiation. They can be divided into adult, fetal, and genital subtypes.

Fetal rhabdomyomas are rarer than the adult subtype and although usually diagnosed at birth, the diagnosis is based on histology rather than patient age.

We present a rare case of a 25-year-old man with a cellular fetal (juvenile) rhabdomyoma, found in the postcricoid region of the hypopharynx.

Cervical rhabdomyoma a rare entity: Case report with review of literature

Genital rhabdomyomas are extremely rare benign tumors of skeletal muscle origin, majority of them being reported in vaginal location. Extensive literature search revealed only three such cases reported in cervix. We hereby report fourth such case of cervical rhabdomyoma in a 35-years-old female patient. The diagnosis was confirmed by histomorphology with desmin and myoD1 positivity on immunohistochemistry. Due to paucity of cases no definite treatment guidelines are available. Differentiation from identical and more common malignant counterpart which is rhabdomyosarcoma is essential to avoid unnecessary aggressive therapy.

Pediatric Benign Tumors With a Skeletal Muscle Component: Myogenin Expression, Diagnostic Pitfalls, and New Molecular Insights

OBJECTIVES

Benign tumors with skeletal muscle differentiation are rare and their characterization in the literature is limited. We present a series of twelve pediatric benign tumors with rhabdomyomatous differentiation including seven rhabdomyomatous mesenchymal hamartomas, four fetal rhabdomyomas, and one benign triton tumor, analyzing myogenic markers as well as clinicopathologic and molecular features. A review of the literature was also performed with an emphasis on myogenic marker expression and correlation with molecular features.

METHODS AND RESULTS

Cases obtained from three tertiary pediatric hospitals were retrospectively reviewed. Eleven of twelve cases expressed myogenin in rare to greater than 15% of cells. Five of nine cases had rare to 70-80% of cells positive for MyoD1. One fetal rhabdomyoma demonstrated homozygous deletions in ZEB2. The benign triton tumor harbored a CTNNB1 mutation. Review of the literature identified 160 pediatric benign tumors with skeletal muscle differentiation of which 9 reported myogenin positivity.

CONCLUSIONS

Myogenin and MyoD1 may be variably expressed in benign lesions with skeletal muscle differentiation. Recognition of key morphologic features remains critical to diagnose these lesions and, in rhabdomyoma, to exclude malignancy. Our series expands the knowledge of the relationship between rhabdomyoma and rhabdomyosarcoma (RMS) by identifying a shared molecular alteration in ZEB2.

Rare Diseases of Larynx, Trachea and Thyroid

This review article covers data on rare diseases of the larynx, the trachea and the thyroid. In particular, congenital malformations, rare manifestations of inflammatory laryngeal disorders, benign and malignant epithelial as well as non-epithelial tumors, laryngeal and tracheal manifestations of general diseases and, finally, thyroid disorders are discussed. The individual chapters contain an overview of the data situation in the literature, the clinical appearance of each disorder, important key points for diagnosis and therapy and a statement on the prognosis of the disease. Finally, the authors indicate on study registers and self-help groups.

Rare Diseases of the Salivary Glands and of Facial Nerve

Salivary gland diseases are rare. In the European Union (EU) a disease is considered to be rare if not more than 5 of 10,000 people are affected by it. According to estimates in Germany are about 4 million people with a rare disease. In the EU are about 30 million people with rare diseases [1]. In the present work most of the described diseases of salivary glands and of the facial nerve fall in this category. They form a very heterogeneous group whose treatment takes place mainly in specialized centers. Still, it is essential for the otolaryngologist to identify and to diagnose these diseases in order to initiate the right therapeutic steps. The work is a compilation of innate andacquired rare salivary gland disorders and of rare facial nerve disorders. The etiologies of inflammatory diseases, autoimmune disorders and tumors are taken into account. For the individual topics, the current literature, if available, was evaluated and turned into summarized facts. In this context the development of new processes, diagnostics, imaging and therapy are considered. Genetic backgrounds of salivary gland tumors and the trends in the treatment of tumorous lesions of the facial nerve are picked up. Furthermore, also rare diseases of the salivary glands in childhood are described. Some of them can occur in adults as well, but differ in frequency and symptoms. Due to the rarity of these diseases, it is recommended to tread these in centers with special expertise for it. Finally, the difficulties of initiation of studies and the problems of establishing disease registries concerning salivary gland disorders are discussed. This is very relevant because these pathologies are comparatively seldom.

Simultaneous Malignant and Benign Nonepithelial Neoplasms of the Larynx-A Case Report and Literature Review

Nonepithelial tumors of the larynx are relatively rare neoplasms of the head and neck. The chondrosarcoma, which develops commonly from cricoid and thyroid cartilage, stands for 0.2% of the laryngeal malignant neoplasms. The rhabdomyoma is even more uncommon benign tumor developing from the laryngeal striated muscles. The clinical manifestation and the treatment options depend on the histopathological evaluation, tumor localization, and its size. In presented case, the simultaneous occurrence of benign and malignant tumors of mesenchymal origin in the patient's larynx was provoking hoarseness, globus sensation, and dysphagia. To the best of authors' knowledge, no other case of the concomitance of rhabdomyoma and chondrosarcoma of the larynx have been reported in the literature.

Histiocyte-rich rhabdomyoblastic tumor: rhabdomyosarcoma, rhabdomyoma, or rhabdomyoblastic tumor of uncertain malignant potential? A histologically distinctive rhabdomyoblastic tumor in search of a place in the classification of skeletal muscle neoplasms

Skeletal muscle tumors are traditionally classified as rhabdomyoma or rhabdomyosarcoma. We have identified an unusual adult rhabdomyoblastic tumor not clearly corresponding to a previously described variant of rhabdomyoma or rhabdomyosarcoma, characterized by a very striking proliferation of non-neoplastic histiocytes, obscuring the underlying tumor. Ten cases were identified in nine males and one female with a median age of 43 years (range 23-69 years). Tumors involved the deep soft tissues of the trunk (N = 4), lower limbs (N = 4), and neck (N = 2). Tumors were well-circumscribed, nodular masses, frequently surrounded by a fibrous capsule containing lymphoid aggregates and sometimes calcifications. Numerous foamy macrophages, multinucleated Touton-type giant cells, and sheets/fascicles of smaller, often spindled macrophages largely obscured the underlying desmin, MyoD1, and myogenin-positive rhabdomyoblastic tumor. Cases were wild type for MYOD1 and no other mutations or rearrangements characteristic of a known subtype of rhabdomyoma or rhabdomyosarcoma were identified. Two of four cases successfully analyzed using a next-generation sequencing panel of 170 common cancer-related genes harbored inactivating NF1 mutations. Next-generation sequencing showed no gene fusions. Clinical follow (nine patients; median 9 months; mean 23 months; range 3-124 months) showed all patients received wide excision; four patients also received adjuvant radiotherapy and none received chemotherapy. At the time of last follow-up, all patients were alive and without disease; no local recurrences or distant metastases occurred. We hypothesize that these unusual tumors represent rhabdomyoblastic tumors of uncertain malignant potential. Possibly over time they should be relegated to a new category of skeletal muscle tumors of intermediate (borderline) malignancy.

Fetal Type Rhabdomyoma of the Soft Palate in an Adult Patient: Report of One Case and Review of the Literature

Rhabdomyoma is a rare benign tumor with skeletal muscle differentiation. Rhabdomyoma is further classified into cardiac, adult, fetal, and genital subtypes. Out of these, fetal type rhabdomyoma (FTR) is the rarest. Only a small number of cases have been recorded in the literature. FTR typically affects male infants and young children and occurs predominantly in the head and neck region. FTR is exceedingly rare in the adult, with less than 30 cases reported. The classic FTR is composed of primitive undifferentiated spindle cells with scant eosinophilic cytoplasm embedded in a myxoid stroma. Immunohistochemically, the tumor cells are positive for desmin, muscle specific actin, and myogenin. Awareness and proper recognition of this rare entity is of considerable importance to avoid misdiagnosis of embryonal rhabdomyosarcoma. In this study, we report one case of FTR in an adult patient and reviewed the literature about the clinical and pathologic presentation of FTR in the adult.

Adult-Type Rhabdomyoma of the Larynx in Birt-Hogg-Dubé Syndrome: Evidence for a Real Association

The autosomal dominant Birt-Hogg-Dubé syndrome is known to be associated with skin, lung and kidney lesions. It is caused by heterozygous germline mutations in the folliculin gene and has a high penetrance. We report the case of a 51 year old woman with Birt-Hogg-Dubé syndrome who presented with a laryngeal mass. Imaging confirmed a mass centered on the piriform sinus and following excision histological examination confirmed the lesion was composed of polygonal cells with abundant eosinophilic cytoplasm consistent with a rhabdomyoma. Laryngeal rhabdomyoma is rare condition and has not been previously described in association with Birt-Hogg-Dubé. In patients with Birt-Hogg-Dubé syndrome who develop upper aerodigestive tract symptoms secondary to mass lesion an adult-type rhabdomyoma might be considered as a differential, with endoscopic excision being the treatment of choice.

Uncommon presentation of a benign nasopharyngeal mass in an adolescent: comprehensive review of pediatric nasopharyngeal masses

Nasopharyngeal masses in the pediatric population are quite rare, and the majority of these are benign. In adolescent boys, there should be a high index of suspicion for juvenile nasopharyngeal angiofibromas. When malignant, the most common lesions encountered are rhabdomyosarcomas, carcinomas, and lymphomas. We report a single case from a tertiary care institution of an adolescent male with an unusual presentation of a benign nasopharyngeal mass and provide a comprehensive review of pediatric nasopharyngeal masses. Whenever possible, radiographic imaging should be obtained, in addition to biopsy, to assist in the diagnosis of pediatric nasopharyngeal masses.

Unusual presentation of extracardiac fetal rhabdomyoma of the larynx in a pediatric patient with tuberous sclerosis

Tuberous sclerosis (TSC) is an autosomal-dominant genetic disease characterized by a spectrum of pathologic manifestations involving skin, brain, kidney, and heart. These manifestations include neuroectodermal, mesodermal, and skin lesions as well as a variety of associated tumors and hamartomas. We report an 11-year-old male with previously diagnosed TSC who presented with a laryngeal mass shown on histology to be fetal cellular rhabdomyoma. Cardiac rhabdomyomas are common in TSC patients, but to our knowledge, the association between TSC and extracardiac rhabdomyomas has not been previously reported.

Voluminous extracardiac adult rhabdomyoma of the neck: a case presentation

Introduction. Rhabdomyomas of the head and neck are exceptionally rare benign mesenchymal tumors. Rare cases have been reported to involve other sites of the body including the head and neck regions. Case Presentation. We report a case of voluminous extracardiac adult rhabdomyoma affecting adult patients and initially seen as slowly growing, indolent neoplasms. The patient is a seventy-year old male Italian patient. Conclusion. Adult extracardiac rhabdomyoma is a rare benign tumor that may present with symptoms that vary from aerodigestive tract obstruction to remaining asymptomatic for many years. Although histology is very characteristic, several differential diagnoses have to be considered. To our knowledge, this is the first case of voluminous adult-type symptomless rhabdomyoma.

Extracardiac juvenile rhabdomyoma of the larynx: a rare pathological finding

The extracardiac juvenile rhabdomyoma is extremely rare in the field of Otorhinolaryngology. The tumour usually arises from the soft tissue of the face or from mucosal sites, especially the oropharynx and the oral cavity but only sporadic endolaryngeal cases have been described in literature so far with predominance of young males. Here, we describe the very rare case of endolaryngeal extracardiac juvenile rhabdomyoma in a 42-year-old male. Clinical examination showed a mass of the right vocal cord, resembling a cystic lesion. Microlaryngoscopy revealed a non-encapsulated lesion and histopathology including immunohistochemistry which consecutively led to the correct diagnosis. This case suggests that the endolaryngeal extracardiac juvenile rhabdomyoma can be easily confused with a vocal cord cyst. Malignant transformations have not been reported but recurrences have been described. When total excision cannot be accomplished, reoperation or narrow follow-up is indicated to prevent advanced revision surgeries.

Adult rhabdomyoma with oncocytic changes affecting the floor of the mouth: optical, immunohistochemical, and ultrastructural study

Adult rhabdomyoma (AR) is an extremely uncommon benign neoplasm with mature skeletal muscle differentiation comprising approximately 2% of muscle tumors, usually affecting the soft tissue of the head and neck. Although histology of AR is characteristic, several differential diagnoses (granular cell tumor, hibernoma, oncocytoma) should be considered, and one needs to be familiar with this rare entity to exclude other neoplastic diseases. We present a case of AR, in a 54-year-old man, affecting the floor of the mouth, and call attention to the oncocytic appearance (including antimitochondrial and peroxiredoxin I immunoreactivity) of this case and its differential diagnosis analyzed at the optical, immunohistochemical, and ultrastructural level, showing the morphological and immunohistochemical features that can be confused with a salivary oncocytoma.

Cytology of a giant adult-type rhabdomyoma of the tongue

Adult rhabdomyoma is a rare primary benign tumour of striated muscle origin that almost exclusively presents in the head and neck region with predilection for male. We herein report a case of an adult rhabdomyoma in a 67-year-old male with cytologic features. The lesions was located in the tongue extended to the left parapharyngeal region. We discuss the cytological findings with a brief review of the literature on this entity.

Spontaneous rhabdomyosarcoma in a young Sprague-Dawley rat

An eight-week-old male Sprague-Dawley (SD) rat showed signs of emaciation, and masses were found in the subcutis around the cervical and thoracic regions. At necropsy, a multilobular mass, 2.2 x 1.8 x 2.0 cm in size, had grown from the left neck into the thoracic cavity. On a cutting surface, masses were firm and whitish to tan, with necrotic and hemorrhagic plaques. Microscopically, masses were composed of multiple nodules of tumor cells that were incompletely encapsulated with fibrous connective tissue. The tumor cells exhibited varied forms, from spindle to globoid shapes with minimal to abundant eosinophilic cytoplasm, and appeared as large, multinucleated cells; many of the tumor cells were vacuolated. Histochemistry results revealed that tumor cells exhibited some cross-striation in the cytoplasm using PTAH staining. There were some multinuclear tumor cells with vacuoles located around the nuclei, and these vacuoles showed reddish staining by the periodic acid Schiff (PAS) method. Immunohistochemical staining also expressed intense granular cytoplasmic staining for desmin and myoglobin, with highly positive staining for PCNA, whereas alpha-smooth muscle actin (alpha-SMA) was negative. Based on the pathology results, a spontaneous rhabdomyosarcoma with pleomorphic type was diagnosed in a young SD rat.