Distinctive soft tissue tumors of the head and neck

Current topics and management of head and neck sarcomas

Given the low incidence, variety of histological types, and heterogeneous biological features of head and neck sarcomas, there is limited high-quality evidence available to head and neck oncologists. For resectable sarcomas, surgical resection followed by radiotherapy is the principle of local treatment, and perioperative chemotherapy is considered for chemotherapy-sensitive sarcomas. They often originate in anatomical border areas such as the skull base and mediastinum, and they require a multidisciplinary treatment approach considering functional and cosmetic impairment. Moreover, head and neck sarcomas may exhibit different behaviour and characteristics than sarcomas of other areas. In recent years, the molecular biological features of sarcomas have been used for the pathological diagnosis and development of novel agents. This review describes the historical background and recent topics that head and neck oncologists should know about this rare tumour from the following five perspectives: (i) epidemiology and general characteristics of head and neck sarcomas; (ii) changes in histopathological diagnosis in the genomic era; (iii) current standard treatment by histological type and clinical questions specific to head and neck; (iv) new drugs for advanced and metastatic soft tissue sarcomas; and (v) proton and carbon ion radiotherapy for head and neck sarcomas.

Myxoid Soft Tissue Tumors: A 20-Year Experience on Fine Needle Aspiration with Application of the Proposed WHO Reporting System for Soft Tissue Cytopathology

INTRODUCTION

Myxoid soft tissue tumors represent a heterogenous group of neoplasms. The study presented our experience on cytopathology of myxoid soft tissue tumors on fine needle aspiration (FNA) and aimed to apply the recently proposed WHO system for reporting soft tissue cytopathology.

MATERIAL AND METHODS

We performed a 20-year retrospective search of our archives to identify all FNAs performed on myxoid soft tissue lesions. All cases were reviewed, and the WHO reporting system was applied.

RESULTS

129 FNAs performed in 121 patients (62 males; 59 females) showed a prominent myxoid component, accounting for 2.4% of all soft tissue FNAs. The FNAs were performed on 111 (86.7%) primary tumors, 17 (13.2%) recurrent tumors, and one (0.8%) metastatic lesion. A spectrum of non-neoplastic and neoplastic lesions including both benign and malignant neoplasms was identified. Overall, the most common tumors identified were myxoid liposarcoma (27.1%), intramuscular myxoma (15.5%), and myxofibrosarcoma (13.1%). The sensitivity and specificity of FNA regarding the nature of the lesion (benign vs. malignant) were 98% and 100%, respectively. When the WHO reporting system was applied, the frequency of the categories was as follows: benign (7.8%), atypical (34.1%), soft tissue neoplasm of uncertain malignant potential (18.6%), suspicious for malignancy (3.1%), and malignant (36.4%). The risk of malignancy calculated in each category was as follows: benign (10%), atypical (31.8%), soft tissue neoplasm of uncertain malignant potential (50%), suspicious for malignancy (100%), and malignant (100%).

CONCLUSION

A diverse group of non-neoplastic and neoplastic lesions can show a prominent myxoid component on FNA. The WHO reporting system for soft tissue cytopathology is easily applicable and appears to correlate well with the malignant potential of myxoid tumors.

Update on MR Imaging of Soft Tissue Tumors of Head and Neck

This article reviews soft tissue tumors of the head and neck following the 2020 revision of WHO Classification of Soft Tissue and Bone Tumours. Common soft tissue tumors in the head and neck and tumors are discussed, along with newly added entities to the classification system. Salient clinical and imaging features that may allow for improved diagnostic accuracy or to narrow the imaging differential diagnosis are covered. Advanced imaging techniques are discussed, with a focus on diffusion-weighted and dynamic contrast imaging and their potential to help characterize soft tissue tumors and aid in distinguishing malignant from benign tumors.

Leiomyoma and Leiomyosarcoma (Primary and Metastatic) of the Oral and Maxillofacial Region: A Clinicopathological and Immunohistochemical Study of 27 Cases

Smooth muscle neoplasms represent an important group of lesions which is rare in the oral cavity. Leiomyoma (LM) is benign smooth muscle/pericytic tumor usually presenting as non-aggressive neoplasm, while leiomyosarcoma (LMS) represents its malignant counterpart. The rarity of these lesions, together with its unspecific clinical presentation and a variable histopathological appearance, lead to a broad list of differential diagnoses, hampering their diagnoses. Therefore, in this study we describe the clinical and microscopic features of a series of oral and maxillofacial LMs and LMSs. A retrospective search from 2000 to 2019 was performed and all cases diagnosed as LM and LMS affecting the oral cavity and gnathic bones were retrieved. Clinical and demographic data were obtained from the patients' pathology records, while microscopic features and immunohistochemistry were reviewed and completed when necessary to confirm the diagnoses. Twenty-two LMs and five LMSs were obtained. In the LM group, males predominated, with a mean age of 45.7 years. The upper lip was the most affected site, and 18 cases were classified as angioleiomyomas and four as solid LM. In the LMS group, females predominated, with a mean age of 47.6 years. The mandible was the most affected site. Diffuse proliferation of spindle cells, with necrosis and mitotic figures, were frequent microscopic findings. LMs and LMSs were positive for α-smooth muscle actin, HHF-35 and h-caldesmon. In conclusion, oral LM/LMS are uncommon neoplasms with the latter usually presenting as metastatic disease. H&E evaluation may be very suggestive of oral LMs, but h-caldesmon staining is strongly recommended to confirm LMS diagnosis.

Solitary extraosseous neurofibroma in a 5-year-old child - A case report

Rationale:

Neurofibroma (NF) is the most common benign peripheral nerve sheath tumour that most often occurs as a solitary tumour. A clinical and imaging diagnosis may be challenging since no distinctive features are unique for this lesion. Solitary NFs are treated by complete resection that may sometimes require a nerve sacrifice, ending with a neurological deficit.

Patient Concerns:

A 5-year-old girl with mild asymptomatic slow-growing swelling in the vestibulum of her right mandible.

Diagnosis:

A solitary variant of extraosseous NF involving the right mental branch of the inferior alveolar nerve.

Treatment:

Surgical removal of the lesion while fully preserving the mental branch.

Outcomes:

No sensory deficit was identified during a 3-month follow-up.

Take-Away Lessons:

Ultrasonography is a valuable tool for evaluating soft-tissue masses of the oral cavity. A solitary extraosseous NF involving the mental branch can be surgically removed without nerve deficit.

Classification and Clinicopathologic Study of Orofacial Mesenchymal Tumors: A Retrospective Study

Aim:

To determine the prevalence of orofacial mesenchymal neoplasms and classify them using the WHO criteria while appraising its applicability.

Materials and Methods:

This was a retrospective study involving a total sample of 192 entries diagnosed as mesenchymal tumors for the period 1990-2018 at the Oral Pathology Department, University College Hospital, Ibadan. The histopathology records were examined and clinicopathological data were obtained. Hematoxylin and Eosin slides of the cases were assessed to confirm the diagnosis. Tumors were classified using the WHO 2013 classification. Data were analyzed and presented using descriptive statistics.

Results:

Orofacial mesenchymal tumors constituted 7.9% of 2402 biopsies. There were 26 diagnoses in 161 tumors of the WHO classification. Male-to-female ratio was 1.1:1. Peak age group was in the third decade. Soft tissue tumors were 61.5%, while bone tumors were 38.5%. Benign tumors constituted 49.5%, while sarcomas and intermediate tumors were 45.8% and 4.7%, respectively. The mandibular region (29.7%) was the most commonly affected site. Adipocytic and osteogenic tumors were the most prevalent tumors in the soft tissue and osteoarticular series, respectively, representing 19.8% and 32.3% of all cases, while orofacial sarcomas constituted 3.6% of all lesions seen.

Conclusion:

The findings in this study are in line with those of previous studies. However, the WHO classification may not be suited for the orofacial region. Crafting of a classification system for mesenchymal tumors of the orofacial region would thus be necessary.

Soft Tissue Special Issue: Perivascular and Vascular Tumors of the Head and Neck

Perivascular and vascular neoplasms of the head and neck are a rare group of tumors comprising a spectrum of clinical/biologic and histological features. They are frequently diagnostically challenging, due to their morphologic and immunohistochemical overlap. In this review, we summarize the pathology of these neoplasms, discussing morphology, immunohistochemistry, associated genetic findings, and the differential diagnoses.

Impact of Surgical Margin in Skull Base Surgery for Head and Neck Sarcomas

Objective  This study aimed to determine the adequate resection margin in skull base surgery for head and neck sarcoma. Design  We retrospectively reviewed 22 sarcomas with skull base invasion. Induction chemotherapy, followed by surgery and postoperative radiotherapy and adjuvant chemotherapy, was performed in 18 patients with chemosensitive sarcomas, and surgery with or without postoperative radiotherapy was performed in four patients with chemoresistant sarcomas. Radical resection was performed in patients with chemosensitive sarcomas with a poor response to induction chemotherapy and in patients with chemoresistant sarcomas. Conservative resection with close surgical margin was performed in patients with chemosensitive sarcomas with a good response to induction chemotherapy. Setting and Participants  This single-centered retrospective study included patients from the National Cancer Center Hospital, Japan. Results  The response to induction chemotherapy was significantly associated with the 3-year local control rate (LCR; good response versus poor response: 100% versus 63%, p  = 0.048). Patients with a good response to chemotherapy had a favorable local prognosis even when the local therapy was conservative resection. In radical skull base surgery, patients whose surgical margins were classified as "wide margin positive" had significantly poorer 3-year LCR than did patients with "margin negative" or "micro margin positive" margins (25% versus 83%, p  = 0.014). Conclusion  Conservative resection with close surgical margins might be acceptable for chemosensitive sarcomas with a good response to chemotherapy. Resection margin status was an important predictive factor for local recurrence after radical skull base surgery. Microscopic microresidual tumor might be controlled by postoperative treatment.

Extracalvarial Composite Infantile Myofibromatosis: Case Report and Literature Review

Infantile soft tissue tumors of the head are very rare and the majority of them are myofibromas. The authors present the case of a 1-day-old boy with a scalp tumor with several distinct histopathological features including myofibroma, hemangiopericytoma, and fibrosarcoma consistent with the diagnosis of composite infantile myofibromatosis. Genetic testing was negative for trisomy 17, translocation (12; 15), FUS, and ETV6 translocations. Despite the ominous histopathological features, the clinical course was benign. The authors review here available literature concerning current concepts of making the diagnosis of composite infantile myofibromatosis and discuss treatment options.

Sinonasal small round blue cell tumors: An approach to diagnosis

The differential diagnosis for small round cell tumors in the sinonasal tract is diverse and as the body of literature documenting not only uncommon presentations but also availability of ancillary studies grows, so does the need for a reminder to take a conservative and thorough approach before rendering a diagnosis. Small tissue samples are particularly problematic, with limitations that include volume of tumor cells available for studies, lack of architectural context and a non-specific gross description. Incorporation of patient history and presentation, radiologic findings, clinical impression and concurrent studies often guide the course of studies performed by the pathologist. If these are non-specific, the pathologist may need to perform ancillary studies, including a broad panel of immunohistochemical stains and molecular studies. If tissue is limited, a precise classification may not be achievable. Although the expectation to render a definitive diagnosis is high, the pathologist should never feel compelled to go further with a diagnosis than the tissue itself supports.

Combined therapy against recurrent and intracranial invasion of sinonasal hemangiopericytoma: A case report

Sinonasal hemangiopericytoma (HPC) is a soft tissue tumor of vascular origin. Open surgical methods and endoscopic techniques are considered the standard treatments for sinonasal HPC. However, local recurrences resulting from residual tumors are common. Adjuvant radiotherapy and chemotherapy have also been used to treat HPC, however, the number of studies which have investigated effective adjuvant treatments in the literature are limited. The current study reports a 42-year-old male with recurrent and intracranial invasion of sinonasal HPC, diagnosed in Xuanwu Hospital (Beijing, China). The patient underwent multiple surgeries to remove the tumors, however, no adjuvant therapy was adopted during this period and the tumors reoccurred within 1 year. On admittance to Tangshan People's Hospital (Tangshan, China), the patient presented with limited mouth opening and chewing ability, and hearing loss. Under observation using an electron microscope, HPC usually consists of spindle-shaped cells with elongated nuclei and displays characteristic staghorn-like vascular channels. In the present case, immunohistochemical studies were performed on paraffin-embedded sections of the tumor. The tumor cells expressed CD34, CD68(+/-), epithelial membrane antigen, CD31, α-actin, desmin, CD99, S-100, B-cell lymphoma-2 and Ki-67 (30%), but were negative for creatine kinase. The patient was treated with intensity-modulated radiotherapy and adjuvant chemotherapy, which demonstrated efficacy. No recurrence and metastasis was observed at the 1 year follow-up subsequent to the combined therapy.

Outcomes of the treatment of head and neck sarcomas in a tertiary referral center

Head and neck sarcomas are a rare and heterogeneous group of tumors that pose management challenges. We report our experience with these tumors. Forty consecutive patients treated for 44 head and neck sarcomas between 1997 and 2014 were culled from our prospectively maintained head and neck database. Five patients were excluded. The adult cohort consisted 29 (83%) patients of a mean age of 57.7 years, with 33 sarcomas. The most common diagnoses were undifferentiated pleomorphic sarcoma (27%) and chondroblastic osteosarcoma (21%). Clear surgical margins were achieved in 24/33 (73%) lesions. Twenty-two patients received radiotherapy and/or chemotherapy. Fourteen patients developed local (n = 6), regional (n = 1) and distant (n = 7) recurrence. The overall 5-year survival was 66% with a mean survival interval of 66.5 months. Recurrent sarcoma, close (<1 mm) or involved surgical margins and advanced age were associated with statistically significantly reduced survival. The pediatric cohort consisted 6 (17%) patients, with a mean age of 9 years. Five patients had primary embryonal rhabdomyosarcomas and one had chondroblastic osteosarcoma. Clear surgical margins were achieved in five (83%) patients. All patients received adjuvant radiotherapy and/or chemotherapy. Mean survival interval was 102 months. Three patients developed local (n = 1) or distant (n = 2) recurrence. Twenty-three free and 8 pedicled flaps were performed in 25 patients. Eleven out of thirty-nine (28%) lesions in 11 patients developed a complication. In conclusion, head and neck sarcomas are best managed by a multidisciplinary team at a tertiary head and neck referral center and resection with clear margins is vital for disease control.

Spindle Cell Carcinoma of the Upper Aerodigestive Tract

Objectives:

We sought to better characterize spindle cell carcinoma (SpCC) of the upper aerodigestive tract, a rare and aggressive variant, through comparison of a large cohort of head and neck SpCCs against a cohort of conventional head and neck squamous cell carcinoma (SCC) patients.

Methods:

We compared epidemiologic and clinicopathologic characteristics of 341 SpCCs with 67 882 SCCs of the head and neck, drawing data from the SEER national database. We also compared disease-specific survivals (DSS) for SpCC and SCC based on tumor site and mode of treatment.

Results:

SpCCs were predominantly laryngeal (46.4%, P < .001) and were more likely to be high grade ( P > .001). SpCCs were also more likely than SCCs to present at an early stage ( P < .001 to P < .05). Rates of distant metastasis were similar between the tumor types. DSS was similar between SpCCs and SCCs, although site-specific survival rates were higher for SpCCs of the larynx ( P = .017) and lower for those of the oral cavity ( P = .008).

Conclusion:

SpCC of the head and neck is more likely than SCC to present at an early stage, with fewer nodal metastases. Survival rates appear to depend on anatomic site as well.

Spindle cell rhabdomyosarcoma: a brief diagnostic review and differential diagnosis

Spindle cell rhabdomyosarcoma is a rare variant of embryonal rhabdomyosarcoma that has a predilection for young males and most commonly involves the paratesticular region followed by head and neck. Histopathology demonstrates elongated spindle cells with fusiform to cigar-shaped nuclei and indistinct eosinophilic cytoplasm arranged in fascicles or whorls. Although the tumor demonstrates increased cellularity and moderate atypia, the microscopic and architectural patterns can allow this tumor to be confused with multiple entities, such as leiomyosarcoma, spindle cell carcinoma, desmoplastic melanoma, or fibrosarcoma, with important therapeutic implications. Immunohistochemical workup demonstrates sarcomeric differentiation with reactivity for desmin, myogenin, and MyoD1 markers. Compared with other subtypes, the spindle cell variant in children is associated with a favorable outcome; however, in the adult population there does not appear to be any prognostic advantage.

Suboccipital malignant solitary fibrous tumor: report of a case

Solitary fibrous tumors (SFTs) are rare soft-tissue sarcomas usually arising in the pleura of the thoracic cavity. Thirty percent of SFTs present in extrapleural locations, and infrequently in the head and neck region. While the majority of SFTs are benign, aggressive variants have been described. We report a case of a patient with a malignant SFT arising in the suboccipital soft tissues of the neck. We elucidate the diagnostic and therapeutic challenges in managing this tumor in this unusual location.

Conservative surgical treatment of tongue hemangiopericytoma

Hemangiopericytoma is a vascular tumor that is believed to arise from the Zimmermann's pericytes, smooth muscles cells localized around the blood vessels. This tumor presents as a slowly enlarging painless mass with a clear predilection for the musculoskeletal system. The aim of this work was to introduce a peculiar case of a tongue hemangiopericytoma managed by conservative surgical treatment.

Inflammatory myofibroblastic tumors of the head and neck: evaluation of clinicopathologic and prognostic features

Head and neck lesions composed of spindle cells evoke a differential diagnosis which includes a host of benign and malignant entities. One of the less common spindle cell lesions in this region is the inflammatory myofibroblastic tumor (IMT). Although IMTs were originally regarded as "pseudotumors", they are now recognized to be true neoplasms. Local recurrence, and, rarely, malignant change have been reported. Currently, the definitive means of diagnosing IMTs is the identification of a rearrangement of the anaplastic lymphoma kinase gene (at chromosome 2p23) by fluorescence in situ hybridization. The histopathologic differential diagnosis includes infectious processes, other fibro-inflammatory lesions, lymphoma, the inflammatory variant of malignant fibrous histiocytoma, and sarcomatoid (spindle cell) carcinoma. Complete surgical excision is the treatment of choice.

High-grade myofibroblastic sarcoma of inguinal region in a dog

A subcutaneous tumor in the left inguinal region was present in an 11-year-old female bloodhound. Histopathologically, the tumor showed invasive growth and extensive necroses, and it was composed of spindle-shaped, elongated, and stellate neoplastic cells accompanied by occasional giant cells arranged in fascicular, herringbone, or irregular storiform patterns with abundant production of collagen fibers. The cytoplasm of most tumor cells was positive for vimentin, alpha-smooth muscle actin, and calponin, but was negative for desmin, smoothelin, and S-100. Furthermore, most of the tumor cells were negative for Iba1 while some tumor cells were weakly positive. Thus, this tumor was diagnosed as a high-grade myofibroblastic sarcoma according to the diagnostic criteria for human myofibroblastic sarcomas.

[Undifferentiated malignant round cell tumors of the sinonasal tract and nasopharynx]

Undifferentiated malignant round cell tumors of the sinonasal tract and nasopharynx comprise of aggressive malignant neoplasms with overlapping morphologic features, which yet are very different and can be identified as carcinoma, lymphoma, sarcoma, melanoma or olfactory neuroblastoma. Differentiating these tumors is important because their treatment and prognosis are quite different. Because of the limited initial biopsy tissue materials, major differential diagnostic difficulties may arise. The use of a panel of immunohistochemical markers and the identification, in some cases, of specific chromosomal translocations are most often required. We describe clinical, morphological, immunohistochemical and molecular features as well as therapeutic management and prognosis of rhabdomyosarcoma (RMS), Ewing sarcoma/primitive neuroectodermic tumor (EWS/PNET), nonkeratinizing nasopharyngeal carcinoma, undifferentiated subtype (UCNT), olfactory neuroblastoma (ONB), small cell carcinoma, neuroendocrine type (SCCNET), sinonasal undifferentiated carcinoma (SNUC) and mucosal melanoma. Mesenchymal chondrosarcoma, small round cell synovialosarcoma, lymphomas and plasmocytoma are not introduced. The most important features of diagnosis will be summarized in two tables.

Pedunculated hemangiopericytoma-like tumor: peculiar fibroepithelial polyp or fibrous histiocytoma variant

Pathologists are continually challenged with the difficult task of discriminating between innocuous disease processes and potentially malignant entities. Apropos of this concern, we present a series of three cutaneous polypoid lesions that simulated fibroepithelial polyp, yet upon close scrutiny yielded histologic features of solitary fibrous tumor (SFT) or hemangiopericytoma. These pedunculated lesions showed a storiform pattern of spindled cells with interspersed gaping vascular channels reminiscent of SFT or hemangiopericytoma. Interestingly, the immunohistochemical staining profile of these lesions was negative for CD34 and positive for bcl-2 and factor XIIIa. These findings were discordant with SFT and suggest a relationship with fibrous histiocytoma. We propose that this entity represents a hitherto described variant of fibrous histiocytoma known as pedunculated hemangiopericytoma-like fibrous histiocytoma.

Sinonasal tract angiosarcoma: a clinicopathologic and immunophenotypic study of 10 cases with a review of the literature

BACKGROUND

Primary sinonasal tract angiosarcoma are rare tumors that are frequently misclassified, resulting in inappropriate clinical management. There are only a few reported cases in the English literature.

MATERIALS AND METHODS

Ten patients with sinonasal tract angiosarcoma were retrospectively retrieved from the Otorhinolaryngic Registry of the Armed Forces Institute of Pathology.

RESULTS

Six males and four females, aged 13 to 81 years (mean, 46.7 years), presented with epistaxis and bloody discharge. Females were on average younger than their male counterparts (37.8 vs. 52.7 years, respectively). The tumors involved the nasal cavity alone (n = 8) or the maxillary sinus (n = 2), with a mean size of 4.3 cm; the average size was different between the genders: males: 2.8 cm; females: 6.4 cm. Histologically, all tumors had anastomosing vascular channels lined by remarkably atypical endothelial cells protruding into the lumen, neolumen formation, frequent atypical mitotic figures, necrosis, and hemorrhage. All cases tested (n = 6) demonstrated immunoreactivity with antibodies to Factor VIII-RA, CD34, CD31, and smooth muscle actin, while non-reactive with keratin and S-100 protein. The principle differential diagnosis includes granulation tissue, lobular capillary hemangioma (pyogenic granuloma), and Kaposi's sarcoma. All patients had surgery followed by post-operative radiation (n = 4 patients). Follow-up was available in all patients: Six patients died with disease (mean, 28.8 months); two patients had died without evidence of disease (mean, 267 months); and two are alive with no evidence of disease at last follow-up (mean, 254 months).

CONCLUSIONS

Sinonasal tract angiosarcoma is a rare tumor, frequently presenting in middle-aged patients as a large mass usually involving the nasal cavity with characteristic histomorphologic and immunophenotypic features. Sinonasal tract angiosarcoma will often have a poor prognosis making appropriate separation from other conditions important.

Postirradiation osteosarcoma of the mandible with heterologous differentiation

Heterologous differentiation in osteosarcoma is rare, with only 17 cases previously described in the literature. We report a case of a mandibular osteoblastic osteosarcoma with rhabdomyosarcomatous differentiation in a 45-year-old man who had a history of Hodgkin lymphoma that was treated with chemotherapy and radiation. Radiographs showed a destructive osteoblastic tumor of the mandible that was proven by biopsy to be osteosarcoma. After the patient underwent neoadjuvant chemotherapy, the tumor was resected. It contained a high-grade osteosarcoma composed of osteoblastic and chondroblastic elements that had no definitive response to therapy. Within the center of the lesion was a discrete focus of pleomorphic cells with rhabdomyosarcomatous differentiation that was confirmed by immunohistochemical stains for desmin, myogenin, and myogenic differentiation antigen 1. The patient received additional chemotherapy and radiation therapy but developed lung, brain, and spinal metastases and died 7 months after surgery. To our knowledge, this is the first report of osteosarcoma of the mandible with heterologous differentiation.

Hemangiopericytoma of the infratemporal fossa: progression toward malignancy in a 30-year history

Hemangiopericytoma is a rare vascular tumor first described by Stout and Murray in 1942 and characterized by a proliferation of Zimmermann's pericytes, smooth muscle cells arranged around blood vessels. This tumor presents as a slowly enlarging painless mass. Diagnosis with certainty is often a difficult one because of the close likeness with other spindle cell tumors; it requires the help of immunohistochemical techniques and sometimes ultrastructural techniques. Only 15% of hemangiopericytomas are localized in the cervicofacial region; in particular, occurrence in the infratemporal fossa is an exceptional occurrence. In this article, we report an unusual case of recidivate hemangiopericytoma of the infratemporal fossa that has progressively assumed features of malignancy over 30 years. The hemangiopericytoma relapse potentiality is elevated, even when the histologic characteristics of the tumor indicate a low aggressivity, and therefore every hemangiopericytoma must be considered to have malignant potential. In conclusion, the unpredictable behavior of hemangiopericytoma requires a radical primary treatment to avoid the risk of relapses that always are frequent and aggressive.

[Ectopic Warthin's tumour in nasopharynx. Revision of one clinical case]

This is a case report of a 69-year-old male patient referred to the ENT out patients with right-sided epistaxis and hipoacusis. Fibroptic examination reveals a cystic lesion at the exit of the right eustachian. A CT scan is informed as a well delimited and rounded-shaped tumour compatible with lymphoma. Excisional biopsy by a nasal rigid endoscopy is practiced and the histology result is Warthin's tumour. The nasopharynx is a rather unusual location for this type of tumours, almost exclusive in origin of major salivary glands. It's highlighted the unforeseeable histological diagnosis in this particular anatomical region, where the clinical differential diagnosis is broad and the access difficult.

Spindle cell rhabdomyosarcoma of the tongue in an infant: a case report with emphasis on differential diagnosis of childhood spindle cell lesions

Malignant tumors are extremely uncommon in infants, specifically in the head and neck region. We present a three-day-old infant with a large, polypoid, soft tissue mass arising from the floor of the mouth. Histologically, this neoplasm consisted of hypercellular and myxoid areas. A mixture of poorly oriented, small, undifferentiated, hyperchromatic, and round to elongate spindle cells was seen. A high degree of striated muscle differentiation was present, along with areas marked by a herringbone pattern, as well as hemangiopericytic vessels and rare mitosis. Immunohistochemical examinations revealed strong nuclear staining for myogenin and diffuse cytoplasmic staining for desmin and muscle-specific actin (HHF-35). The tumor did not stain for S-100. Based on histologic results and immunostains, this lesion was diagnosed as spindle cell rhabdomyosarcoma. This type of lesion involving the tongue is rarely seen in females, neither in association with a herringbone pattern nor with hemangiopericytic vessels. Furthermore, rare benign and malignant spindle lesions, such as cellular fibromatosis, fetal rhabdomyoma, infantile hemangiopericytoma, infantile rhabdomyofibrosarcoma, and infantile fibrosarcoma, should be in the differential diagnosis and excluded.

Solitary central myofibroma presenting in the gnathic region

Solitary myofibroma of adults is an uncommon neoplasm that typically arises in soft tissue and subcutaneous sites in the head and neck, but rarely within bone. When encountered in the jaws, the lesions exhibit clinical and radiographic features suggestive of an odontogenic tumor or cyst as well as several other neoplastic conditions. Tooth mobility, displacement of teeth, and dramatic jaw expansion may be observed. Analogous to other sites of involvement, gnathic myofibromas are biologically indolent and show little or no recurrence following excision. In rare instances, however, the ability to obtain adequate surgical margins by conservative measures may be limited; thus, issues of local control may supercede the importance of biologic potential. We present the radiologic and histopathologic findings in a case of central myofibroma presenting as a large lytic lesion of the mandible. Myofibroma involving the jaw bones represents a unique diagnostic and therapeutic challenge, and accurate diagnosis and management is predicated on careful correlation of radiographic and pathologic findings.

Two unusual lesions in the nasal cavity of infants--a nasal chondromesenchymal hamartoma and an aneurysmal bone cyst like lesion. More closely related than we think?

Benign reparative lesions in the head and neck region in infants are rare and often difficult to classify on histology. Discussed herein are two rare lesions in infants occurring at identical locations in the nasal cavity with striking histologic similarity but different histologic labels. One was a case of nasal chondromesenchymal hamartoma (NCMH) occurring in a 1-year-old child and the other an aneurysmal bone cyst (ABC) like lesion affecting a 4-month infant. Both these lesions were locally destructive and had nearly similar clinical presentation. Both on immunohistochemistry showed myofibroblastic nature and had similar histology except that the ABC like lesion lacked the cartilage component of the former. In view of great similarity in the two lesions, it was thought that the second lesion might also represent a reparative, non-cartilage-containing counterpart of the former.

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature

Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting. The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO. Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors. Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO. The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied. Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed. The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years). A long history of OO was common. The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9). The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 1.7 to 14 cm. Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification. Four of these benign-appearing PMTMCTs contained osteoid-like matrix. Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant. The 3 cases without known OO were histologically identical to the typical PMTMCT. Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma. Three cases expressed actin; all other markers were negative. Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR. Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases). We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT. Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors. Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO.

Schwannoma of the sinonasal tract: a clinicopathologic and immunohistochemical study of 5 cases

CONTEXT

Peripheral nerve sheath tumors are soft tissue neoplasms rarely encountered in the nasal cavity and paranasal sinuses.

OBJECTIVE

To describe the clinicopathologic and immunohistochemical features of a series of schwannomas of the sinonasal tract.

DESIGN

Surgical pathology files were searched for the diagnosis "sinonasal schwannoma." All histologic documents and clinical data were reviewed. Immunohistochemistry was performed on paraffin-embedded tissue with antibodies to S100 protein, epithelial membrane antigen, CD34, and MIB-1. RESULSTS: Five cases of sinonasal schwannoma were retrieved; patients included 3 women and 2 men, aged 20 to 56 years. Three cases were located in the ethmoid sinus. Clinical symptoms were nonspecific (nasal obstruction, epistaxis, and anosmia). All tumors were treated with conservative surgical resection. Pathologic examination showed a spindle cell proliferation without encapsulation in all cases. No cytologic atypia was seen, and the mitotic activity was low (<3 mitotic figures/10 high-power fields). Immunohistochemistry showed diffuse positivity with S100 protein and negativity with CD34 and epithelial membrane antigen. MIB-1 staining was low (1%-5% of tumor cell nuclei stained). During the follow-up (median, 6 years), no recurrence or metastasis was observed.

CONCLUSIONS

Schwannoma is a very unusual tumor of the sinonasal tract and is associated with nonspecific symptoms. Histologically, sinonasal schwannomas differ from schwannomas of other locations by their lack of a peripheral capsule and possible ulceration of the epithelial covering. Sinonasal schwannomas are treated with conservative surgical resection and have an excellent prognosis.

Oral spindle cell neoplasms: a review of 307 cases

The infrequent exposure of pathologists to soft tissue spindle cell neoplasms coupled with overlapping histologic patterns can often make diagnosis challenging. We reviewed all nonodontogenic spindle cell neoplasms seen between 1982 and 2002 (86,162 total accessions). Diagnoses were reclassified according to current standards supplemented with immunohistochemistry. Of the 307 neoplasms reviewed (0.36% of total accessions), neural tumors were the most common benign entities, accounting for 21% of total cases. Kaposi's sarcoma was the most common malignancy, accounting for 67% of all cases. Diagnoses were revised for 57 cases. Schwannoma and neurofibroma were most commonly revised to palisaded encapsulated neuroma. There were 8 myofibromas and 1 inflammatory myofibroblastic tumor. There were no oral leiomyomas; that is, all 4 originally reported cases were reclassified as myofibroma, palisaded encapsulated neuroma, and solitary fibrous tumor. With the exception of Kaposi's sarcoma, oral soft tissue sarcomas were rare; most benign lesions were neural in origin. The relatively high prevalence of some tumors, such as myofibroma, likely reflects the use of immunohistochemistry in the diagnosis of spindle cell tumors.

Gene expression in neoplasms of the pancreas: applications to diagnostic pathology

It seems that, lately, every pathology journal has three or four articles documenting the discovery of another genetic alteration or describing global gene expression in a series of cancers. Although these discoveries provide insight into the biology of neoplasia, it is less clear how they can be quickly and efficiently translated to patient care. This review will use neoplasms of the pancreas as a model and show how recent discoveries of genetic alterations and gene expression patterns can have a significant impact on the diagnosis and even treatment of tumors. Emphasis will be placed on applications that are practical and useful to the daily practice of pathology.