Clinicopathological analysis of head and neck rhabdomyosarcoma: A series of 10 cases and literature review

Paediatric head and neck malignant neoplasms: A brazilian retrospective study

BACKGROUND

To assess the prevalence of oral and maxillofacial malignant neoplasias in children and adolescents diagnosed through biopsies sent to the Oral Pathology Laboratory at the University of Sao Paulo School of Dentistry.

MATERIAL AND METHODS

A retrospective analysis of anatomopathological reports on patients between 1 and 18 years old issued by the oral and maxillofacial pathology laboratory between 1997 and 2021 was performed for demographic data, lesion site, type of biopsy, diagnostic hypothesis and final diagnosis.

RESULTS

The laboratory issued 76,194 anatomopathological reports during this period, of which 10.77% were of children and adolescents. Of this total, only 32 biopsies (32/8.204; 0.39%) were neoplasias in children and adolescents. Sarcomas were the most prevalent malignant neoplasms (19/32; 59%), followed by carcinomas (7/32; 22%), lymphomas (5/32; 16%) and ganglioneuroblastomas (1/32; 3%). Of these 32 patients, the most affected individuals were aged between 4 and 11 years old (47%), 18 (56%) were male, and the mandible was the main anatomical site involved (28%). In 41% of the cases (13/32), the diagnostic hypothesis of the biopsied lesion was mistakenly considered benign and there was no diagnostic hypothesis in 18% of the cases.

CONCLUSIONS

Oral and maxillofacial malignant neoplasms in children and adolescents are uncommon and the accuracy of provisional diagnoses is low in these cases. Better knowledge on oral and maxillofacial malignant lesions in this population would help professionals to reduce the diagnostic time and consequently improve the patient's prognosis.

circ-ZNF609: A potent circRNA in human cancers

Circular RNAs (circRNAs) are a novel group of endogenous RNAs with a circular structure. Growing evidence indicates that circRNAs are involved in a variety of human diseases including malignancies. CircRNA ZNF609 (circ‐ZNF609), derived from the ZNF609 gene sequence, has been demonstrated to be involved in the development and progression of many diseases. circ‐ZNF609 is thought to be a viable diagnostic and prognostic biomarker for several diseases and might be a new therapeutic target, but further research is needed to accelerate clinical application. Here, we review the biogenesis and function of circRNAs and the functional roles and molecular mechanism related to circ‐ZNF609 in neoplasms and other diseases.

When a stuffy nose won't go away: Rhabdomyosarcoma masquerading as adenoiditis

Embryonal Rhabdomyosarcoma is a malignant mesenchymal proliferation of immature skeletal muscle and may arise in children in the orbit, middle ear, nasal cavity, paranasal sinuses, or nasopharynx. Clinical diagnosis may be difficult in a subset of patients who have no significant deformities or irregularities upon visual inspection of the oropharynx. Rhabdomyosarcoma in this setting may be mistaken for a more common underlying etiology such as an upper respiratory infection. We report a case of a 7-year-old male with embryonal variant rhabdomyosarcoma previously misdiagnosed by 3 different physicians to be adenoiditis based on clinical exam and laryngoscopy. This case highlights the capacity for rhabdomyosarcoma to mimic commonly encountered adenoiditis. It also serves as a reminder to maintain a high level of diagnostic vigilance and clinical suspicion of noninfectious etiologies when symptoms persist and are refractory to standard treatment.

Etiologies of Proptosis: A review

Proptosis, the protrusion of the eyeball from the orbit, results from a wide variety of pathologies that can be vision- or life-threatening. Clinical history, associated physical exam findings, and imaging features are all crucial in establishing the underlying etiology. The differential diagnosis is broad, and includes infectious, inflammatory, vascular, and neoplastic entities that range from benign and indolent, to malignant and aggressive. While treatment varies significantly based on the disease process, all are aimed at preserving vision, salvaging the globe, preventing disfigurement, and reducing mortality. Both internists and general ophthalmologists should be familiar with the causes of proptosis in order to initiate the work-up for, and appropriately triage, affected patients.

Proliferative myositis and nodular fasciitis: a retrospective study with clinicopathologic and radiologic correlation

Proliferative myositis (PM) and nodular fasciitis (NF) are two diseases easily misdiagnosed as cancer, often promoting unnecessary invasive procedures. To make accurate diagnoses of PM and NF and for the differential diagnosis between them, we performed a retrospective study to evaluate the roles of the clinical, radiologic, and pathologic characteristics of PM and NF. With an emphasis on the clinicopathologic and radiologic characteristics, we conducted a retrospective study of 8 cases of PM and 64 cases of NF that were diagnosed between 2012 and 2018. According to MRI findings, the lesions of PM and NF appeared as homogeneous masses with homogenous hypointensity or isointensity on T1-weighted images and as moderately or markedly hyperintense signals on T2-weighted images compared to skeletal muscle. In terms of histopathologic features, the differences between PM and NF mainly consisted of the presence of ganglion-like myofibroblasts with vesicular nuclei and basophilic cytoplasm in PM. The areas abundant in myxoid stroma with inflammatory infiltration that did not have abundant ganglion-like cells suggest NF. Immunohistochemically, the spindle-shaped cells of PM stained positive for smooth muscle actin (SMA), while the ganglion-like cells were negative. The spindle-shaped cells of NF showed diffuse expression of SMA, calponin, and vimentin. Our comprehensive study further demonstrated that PM and NF had a wide clinicopathologic and radiologic spectrum. Correlation with the clinical, radiologic and pathologic characteristics may help clinicians and pathologists make accurate diagnoses.

Metastasis in the wild: investigating metastasis in non-laboratory animals

Humans are not the only species to spontaneously develop metastatic cancer as cases of metastasis have been reported in a wide range of animals, including dinosaurs. Mouse models have been an invaluable tool in experimental and clinical metastasis research, with the use of genetically-engineered mouse models that spontaneously develop metastasis or ectopic/orthotopic transplantation of tumour cells to wildtype or immunodeficient mice being responsible for many key advances in our understanding of metastasis. However, are there other species that can also be relevant models? Similarities to humans in terms of environmental exposures, life-span, genetics, histopathology and available therapeutics are all factors that can be considered when looking at species other than the laboratory mouse. This review will explore the occurrence of metastasis in multiple species from a variety of domestic, captive and free-living veterinary cases to assist in identifying potential alternative experimental and clinical research models relevant to humans.

Embryonal Rhabdomyosarcoma (Botryoid Subtype) Affecting the Buccal Mucosa

Rhabdomyosarcoma (RMS) is a rare oral malignant soft tissue tumor whose pathological features may influence the clinical behavior, treatment and prognosis of the lesion. We report a case of a 13-year-old female patient, presenting an asymptomatic polypoid swelling in the left buccal mucosa that was approximately 2.5 cm in diameter and 3 months evolution. The presumptive diagnosis was fibrous hyperplasia and an excisional biopsy was carried out. Pathologic analysis revealed proliferation of predominantly ovoid cells, with eosinophilic cytoplasm and pleomorphic nuclei, arranged in subepithelial cambium layer. The mucosal surface presented a papillary-verrucous appearance. Immunohistochemical analysis revealed intense positivity for desmin, myogenin and Ki-67. The diagnosis was of embryonal RMS (botryoid variant). The patient was subjected to complementary chemotherapy and radiotherapy, with no evidence of recurrence or metastatic disease after 12 months follow-up. A discussion on the clinical, histopathological, immunohistochemical and therapeutic aspects of botryoid RMS will be provided.