Ultrastructure of a hemangiopericytoma and a glomus tumor

CARMN-NOTCH2 fusion transcript drives high NOTCH2 expression in glomus tumors of the upper digestive tract

Glomus tumors (GTs) are perivascular tumors mostly occurring in the distal extremities. Rare cases arise in the digestive tract and may be misdiagnosed with neuroendocrine or gastrointestinal stromal tumors. We aimed to specify the features of GT of the upper digestive tract. Clinical, histological, phenotypic, and molecular features of 16 digestive GTs were analyzed, of whom two underwent whole exome and RNA sequencing to search for gene alterations. RNA-sequencing disclosed a t(1:5)(p13;q32) translocation, which resulted in the fusion of CARMN and NOTCH2 in two GTs. The fusion gene encoded a protein sequence corresponding to the NOTCH2 intracellular domain that functions as transcription factor. These finding was supported by high expression of genes targeted by NOTCH. The CARMN-NOTCH2 translocation was detected in 14 out of 16 (88%) GTs of the upper digestive tract; but in only in two out of six cutaneous GTs (33%). Most digestive GT arose from the stomach (n = 13), and the others from duodenal (2) or oesophagous (1). Nuclear expression of NOTCH2 was detected in the 14 cases containing the fusion transcripts. The CARMN-NOTCH2 fusion transcript may contribute to activation of the NOTCH2 pathway in GT and drive tumor development. The high frequency of this translocation in GT of the upper digestive track suggest that detection of nuclear NOTCH2 expression may be useful diagnostic biomarker of these tumors.

18F-FDG PET/CT of Benign Tracheal Glomus Tumor

Glomus tumors are tumors that arise from the glomus bodies, which can be found in sites of arteriovenous anastomosis. Glomus tumors can occur in all parts of the body but rarely occur in the trachea. The PET/CT findings of these tumors are similar to those of malignant tracheal tumors. We reported the PET/CT findings of a pathologically proven primary glomus tumor in the trachea of a 41-year-old man.

Treatment of primary tracheal glomus tumors: Two case reports and a literature review

RATIONALE

Glomus tumors (GTs) are rare soft tissue neoplasms. Several treatment options have been reported for tracheal GTs including thoracotomy, bronchoscopic electrocautery, Nd: YAG laser, and cryotherapy. However, few studies have evaluated the ideal treatment for tracheal GTs.

PATIENT CONCERNS

A 30-year old man who presented with cough, and expectoration for 1 month, and who had been diagnosed as having a tracheal neoplasm by cervical, and thoracic computed tomography (CT). The patient was a47 years old man. He was admitted to our hospital presenting with intermittent hemoptysis for 3 years. Thoracic CT revealed a round tumor on the right posterior tracheal wall.

DIAGNOSES

Both of them were diagnosed as benign GTs. Histopathology of the tumor showed clusters of round epithelioid cells with eosinophilic cytoplasm, and uniform round to ovoid nuclei surrounding dilated capillaries. Immunohistochemical staining was positive for smooth muscle actin (SMA).

INTERVENTIONS

The tracheal tumor of first patient was located at the level of C7-T1. Tumor resection was performed under fiberoptic bronchoscopy. The tracheal tumor in second patient was located in the lower trachea. Surgical tracheal resection and anastomosis were performed.

OUTCOMES

Both of them achieved good results and no recurrence was seen at the final follow-up LESSONS:: We recommend choosing the most appropriate approach to manage tracheal GTs based on patients' general condition, and tumor characteristics to obtain an excellent prognosis. Our 2 cases of tracheal GT were managed by different approaches, and both achieved good results.

Case report of malignant pulmonary parenchymal glomus tumor: imaging features and review of the literature

Glomus tumor is rare tumor which arises from glomus body and is most frequently found in the soft tissue of the extremities. The lung is a rare ectopic site, and a malignant glomus tumor arising from pulmonary parenchyma is particularly uncommon. To deepen our understanding on their imaging features, we report a case of malignant glomus tumor of pulmonary parenchyma confirmed with surgical histopathology and immunochemistry and review the medical literature on pulmonary parenchymal glomus tumors with emphasis on their imaging features.

The pericyte antigen RGS5 in perivascular soft tissue tumors

Perivascular soft tissue tumors are relatively uncommon neoplasms of unclear lineage of differentiation, although most are presumed to originate from or differentiate to pericytes or a modified perivascular cell. Among these, glomus tumor, myopericytoma, and angioleiomyoma share a spectrum of histologic findings and a perivascular growth pattern. In contrast, solitary fibrous tumor was once hypothesized to have pericytic differentiation--although little bona fide evidence of pericytic differentiation exists. Likewise the perivascular epithelioid cell tumor (PEComa) family shares a perivascular growth pattern, but with distinctive dual myoid-melanocytic differentiation. RGS5, regulator of G-protein signaling 5, is a novel pericyte antigen with increasing use in animal models. Here, we describe the immunohistochemical expression patterns of RGS5 across perivascular soft tissue tumors, including glomus tumor (n = 6), malignant glomus tumor (n = 4), myopericytoma (n = 3), angioleiomyoma (n = 9), myofibroma (n = 4), solitary fibrous tumor (n = 10), and PEComa (n = 19). Immunohistochemical staining and semi-quantification was performed, and compared to αSMA (smooth muscle actin) expression. Results showed that glomus tumor (including malignant glomus tumor), myopericytoma, and angioleiomyoma shared a similar diffuse immunoreactivity for RGS5 and αSMA across all tumors examined. In contrast, myofibroma, solitary fibrous tumor and PEComa showed predominantly focal to absent RGS5 immunoreactivity. These findings further support a common pericytic lineage of differentiation in glomus tumors, myopericytoma and angioleiomyoma. The pericyte marker RGS5 may be of future clinical utility for the evaluation of pericytic differentiation in soft tissue tumors.

Pericyte Antigens in Perivascular Soft Tissue Tumors

INTRODUCTION

Perivascular soft tissue tumors are relatively uncommon neoplasms of unclear line of differentiation, although most are presumed to originate from pericytes or modified perivascular cells. Among these, glomus tumor, myopericytoma, and angioleiomyoma share a spectrum of histologic findings and a perivascular growth pattern. In contrast, solitary fibrous tumor (previously termed hemangiopericytoma) was once hypothesized to have pericytic differentiation.

METHODS

Here, we systematically examine pericyte immunohistochemical markers among glomus tumor (including malignant glomus tumor), myopericytoma, angioleiomyoma, and solitary fibrous tumor. Immunohistochemical staining and semiquantification was performed using well-defined pericyte antigens, including αSMA, CD146, and PDGFRβ.

RESULTS

Glomus tumor and myopericytoma demonstrate diffuse staining for all pericyte markers, including immunohistochemical reactivity for αSMA, CD146, and PDGFRβ. Malignant glomus tumors all showed some degree of pericyte marker immunoreactivity, although it was significantly reduced. Angioleiomyoma shared a similar αSMA + CD146 + PDGFRβ+ immunophenotype; however, this was predominantly seen in the areas of perivascular tumor growth. Solitary fibrous tumors showed patchy PDGFRβ immunoreactivity only.

DISCUSSION

In summary, pericyte marker expression is a ubiquitous finding in glomus tumor, myopericytoma, and angioleiomyoma. Malignant glomus tumor shows a comparative reduction in pericyte marker expression, which may represent partial loss of pericytic differentiation. Pericyte markers are essentially not seen in solitary fibrous tumor. The combination of αSMA, CD146, and PDGFRβ immunohistochemical stainings may be of utility for the evaluation of pericytic differentiation in soft tissue tumors.

Regression of a paraganglioma tumor of the orbit

PURPOSE

To describe a clinical case of an orbital paraganglioma that displayed regression after biopsy alone.

METHODS

Case report.

RESULTS

A 75-year-old female was examined for a right orbital tumor suspected to be metastatic breast carcinoma. An orbital biopsy was performed with significant hemorrhage encountered requiring extensive cautery. There was apparent clinical regression of the tumor with no signs of proptosis or eye movement restriction two years after this patient's biopsy. Histology was consistent with paraganglioma (glomus tumor).

CONCLUSION

Although we cannot rule out spontaneous regression of this unique tumor, we postulate that tissue necrosis caused by the use of cautery induced regression. Unless encapsulated and easily accessible, we suggest that the best management of this rare tumor is that of observation after being found negative for malignancy by biopsy given their propensity for slow progression and in rare cases, regression.

Glomus tumor in the lung parenchyma

Glomus tumors are uncommon lesions of glomus cell origin with ultrastructural and immunohistochemical features of smooth muscle. In the majority of the cases reported in the literature glomus tumors are benign, but there are some rare cases in which they demonstrate aggressive and malignant clinical and histological features. Glomangiosarcomas of the lung are extremely rare malignant tumors, because of the fact that glomus bodies are rare or absent. Due to their rarity they are misdiagnosed. Surgical resection is considered to be the most effective treatment for this condition. We report a case of a 35 year old female with a pulmonary glomangiosarcoma.

Multiple glomangiomas involving the glans penis in pediatric patient

Glomus tumors, especially multiple ones, are uncommon skin and soft tissue neoplasms occasionally seen in various internal organs. Involvement of the external genital organs including penis is extremely rare, and until now, scarce cases have been reported in the available literature.

MATERIALS AND METHODS

A routine histologic and immunohistochemical staining for pan-muscle actin, α-smooth muscle actin, desmin, CD31, and CD34 was applied for diagnosis of the lesions.

RESULTS

Three soft, bluish, and tender tumors localized on the ventral aspect of the glans penis in a 9-year-old boy were found. Furthermore, 3 other lesions situated on the fingers and the plantar surface of the foot were later sequentially noted. Local excisions of all tumors were performed, and glomangiomas were diagnosed based on typical microscopic features as well as immunohistochemical findings, that is, positive immunoexpression for actin but negative for desmin, CD31, and CD34. No recurrence was noted during the 5-year follow-up.

CONCLUSIONS

On the basis of our experience, conservative surgical procedure is sufficient for penile glomus tumors. However, each patient should be carefully examined for possible extragenital lesions.

Glomus tumor and knee pain: a report of four cases

We present four cases of glomus tumors presenting as knee pain. All cases were treated by surgical excision of the tumor. All patients made an immediate recovery with return to full normal function. The presentation of this is unique in that the patient has exquisite pain and tenderness when the area affected is palpated. Occasionally, local infiltration or an ischaemia test can assist with diagnosis. To our knowledge, this is the largest case series in the literature.

Pulmonary lipomatous hemangiopericytoma: report of a rare tumor and comparison with solitary fibrous tumor

Lipomatous hemangiopericytoma is a rare mesenchymal tumor showing areas of lipid-containing cells admixed with a spindle-cell component. Like other hemangiopericytomas, it shows a similar vascular pattern to solitary fibrous tumor and, partly for this reason, it and other hemangiopericytomas have been subsumed into solitary fibrous tumor. The present study provides a comprehensive documentation of a single case of pulmonary lipomatous hemangiopericytoma of the lung, the first to be described at this site, and compares it with solitary fibrous tumor, in terms of clinical, histological, immunohistochemical, ultrastructural, and cytogenetic findings. Apart from the lipid-laden-cell component, pulmonary lipomatous hemangiopericytoma and solitary fibrous tumor were similar histologically. Bcl-2 was positive in both. CD34 was minimally expressed in pulmonary lipomatous hemangiopericytoma, which possessed some non-descriptive intercellular junctions, a feature shared by solitary fibrous tumor, which was CD34 positive. However, one of the latter was rich in gap junctions, a feature consistent with strong connexin (Cx) 43 staining and the existence, hitherto unappreciated, of a CD34/Cx43-positive tumor cell network. In pulmonary lipomatous hemangiopericytoma, chromosomal deletions of 43-44, X, -Y were found. In solitary fibrous tumor, 46, XY, del(13)(q?) abnormalities and abnormalities involving chromosome 10 were frequently observed. These similarities and differences are discussed in the context of the currently favored diagnostic fusion of hemangiopericytoma and solitary fibrous tumor.

Sino-nasal haemangiopericytoma

Hemangiopericytomas are very rare soft tissue tumors of vascular origin featurding pericyts distributed around vascular spaces. They have unpredictable biological behavior and a high local recurrence rate. Silver reticulin stain is essential for their histologic diagnosis. Approximately one third occur in the head and neck. Metastases occurs in nearly one half of all cases. They are relatively radioresistant despite their great vascular component. Wide local excision of the lesion, whenever feasible and lifelong follow-up should be the treatment of choice.

Complete pain relief following treatment of a glomangiomyoma with the pulsed dye laser

Hereditary multiple glomus tumours constitute an autosomal dominant skin disease which is known to demonstrate cutaneous mosaicism typified by type 1 and 2 segmental arrangements. We report a patient with type 2 segmental multiple glomangiomyomas who was disturbed by the pain of her lesions. A symptomatic lesion was successfully treated with the pulsed dye laser and to date there has been no recurrence of the pain. Possible explanations for the clinical response are discussed.

Sinonasal-type hemangiopericytoma: a clinicopathologic and immunophenotypic analysis of 104 cases showing perivascular myoid differentiation

Sinonasal-type hemangiopericytoma is an uncommon upper aerodigestive tract tumor of uncertain cellular differentiation. We report 104 cases of sinonasal-type hemangiopericytoma diagnosed between 1970 and 1995 from the files of the Armed Forces Institute of Pathology. There were 57 females and 47 males ranging in age from 5 to 86 years (mean 62.6 years). The most common clinical presentation was airway obstruction (n = 57) and/or epistaxis (n = 54), with symptoms averaging 10 months in duration. The tumors involved the nasal cavity alone (n = 47) or also a paranasal sinus (n = 26), were polypoid, and measured an average of 3.1 cm. Histologically, the tumors were submucosal and unencapsulated and showed a diffuse growth with fascicular (n = 37) to solid (n = 50) to focally whorled (n = 7) patterns. The tumor cells were uniform in appearance with minimal pleomorphism and had spindle-shaped (n = 82) to round/oval (n = 18) nuclei with vesicular to hyperchromatic chromatin and eosinophilic to amphophilic to clear-appearing cytoplasm with indistinct cell borders. Multinucleated (tumor) giant cells were identified in a minority of cases (n = 5). Mitotic figures were inconspicuous and necrosis was absent. The tumors were richly vascularized, including staghorn-appearing vessels that characteristically had prominent perivascular hyalinization (n = 92). An associated inflammatory cell infiltrate that included mast cells and eosinophils was noted in the majority of cases (n = 87). The immunohistochemical profile included reactivity with vimentin (98%), smooth muscle actin (92%), muscle specific actin (77%), factor XIIIa (78%), and laminin (52%). Surgery was the treatment of choice for all of the patients; adjunctive radiotherapy was given to four patients. Recurrences developed in 18 patients within 1-12 years from diagnosis. Ninety-seven patients were either alive (n = 51, mean 16.5 years) or dead (n = 46, mean 9.6 years) but free of disease. Four patients had disease at the last follow-up: three died with disease (mean 3.6 years) and one patient is alive with disease (28.3 years). Recurrent tumor (17.8%) can be managed by additional surgery. The majority of sinonasal-type hemangiopericytomas behave in a benign manner with excellent long-term prognosis (88% raw 5-year survival) following surgery alone. Sinonasal-type hemangiopericytomas have a characteristic light microscopic appearance with an immunophenotypic profile resembling that of glomus tumors.

Gastrointestinal glomus tumors: a clinicopathologic, immunohistochemical, and molecular genetic study of 32 cases

Glomus tumors usually occur in the peripheral soft tissues, but similar tumors have also been reported in the stomach and occasionally in the intestines. However, the relationship of these tumors to peripheral glomus tumors and gastrointestinal stromal tumors has not been fully clarified because previous series of gastrointestinal glomus tumors predate availability of immunohistochemistry. This clinicopathologic study examined 32 gastrointestinal glomus tumors. All but one of the tumors were located in the stomach and the remaining tumor was from the cecum. The tumors occurred with a strong female predominance (23 females and 9 males) and a median age of 55 years (range 19-90 years). The gastric tumors typically presented with gastrointestinal bleeding or ulcer-like symptoms, and 14 tumors had mucosal ulceration. Five tumors were incidental findings. The tumor sizes varied from 1.1 to 7 cm (median 2 cm), and most were located in the antrum. Histologically, the tumors typically had a solid pattern of sharply demarcated, round glomus cells with prominent, mildly dilated pericytoma-like vessels. Vascular invasion and focal atypia were relatively common (seen in 11 and 13 cases, respectively), and low mitotic activity (1-4 per 50 high power fields), was seen in 10 cases. Immunohistochemically, all tumors were positive for alpha-smooth muscle actin and calponin, and nearly all had a net-like pericellular laminin and collagen type IV positivity. All tumors were negative for desmin and S-100 protein. Three tumors had focal synaptophysin positivity, but none was positive for chromogranin. All tumors lacked KIT expression and the GIST-specific mutations in the c-kit gene. Follow-up revealed one patient death of metastatic disease to liver at 50 months; this tumor had 1 mitosis per 50 high power fields, but had spindle cell foci, mild atypia, and vascular invasion. Thirteen patients were well and alive after long-term follow-up. Gastrointestinal glomus tumors occur almost exclusively in the stomach, and they have a good overall prognosis, but a small, unpredictable potential for malignant behavior exists. These tumors are phenotypically similar to peripheral glomus tumors and differ from epithelioid GISTs.

Fine structure of the human coccygeal body: a light and electron microscopic study

There is only limited data on the microscopic structure of the coccygeal body in classical textbooks. Although there are several articles describing the light microscopic structure of the organ, the data presented are rather conflicting especially when comparing glomus tumors and normal coccygeal bodies. We therefore examined the pericoccygeal soft tissues histologically with the aim of obtaining further evidence. At the light microscopic examination, coccygeal bodies were distinguished as sections of several blood vessels encapsulated by a connective tissue capsule. Small arteries within the coccygeal bodies had an unusual endothelial lining, resembling pseudostratified epithelium or neuro-epithelium. We observed increased numbers of glomus cells in a few samples. A highly tortuous course run by the small arteries was observed in the serial sections. At their electron microscopic examination, endothelial cells exhibited the features of columnar epithelial cells, though some appeared to be vacuole rich. The basal surface of the cells showed basal infoldings, but not as extensive as those of absorptive cells. External lamina, subplasmalemmal vesicles, bundles of microfilaments, groups of membrane bound organelles including mitochondria and endoplasmic reticulum were observed in glomus cells. In conclusion, it is rather difficult to use the term tumor for the coccygeal bodies when relying solely on the number of cells observed, because some segments of the coccygeal bodies were rich in glomus cells. It is more likely that the coccygeal bodies show variability in different individuals. The characteristics of the endothelium of the small arteries in coccygeal bodies needs to be examined in a wider range of specimens in order to be validated as a unique entity.

Hereditary multiple glomangiomas

Hereditary multiple glomangiomas are an interesting rare problem which can either present as multiple painful cutaneous lesions or, rarely, a cosmetic challenge due to site, size or number of lesions. It may also pose a diagnostic dilemma, which can only be settled by biopsy. Malignant change in glomangioma is extremely rare and only a few cases are well documented in literature. A case report of this condition, along with extensive review of the literature, is presented. The prognosis of various forms of glomangiomas and efficacy of diagnostic and therapeutic tools is discussed.

Cutaneous vascular proliferation. Part II. Hyperplasias and benign neoplasms

This second part of our review about vascular proliferations summarizes the clinicopathologic features of the cutaneous vascular hyperplasias and benign neoplasms. Hyperplasias comprise a heterogeneous group of vascular proliferations that eventually show a tendency to regression. Angiolymphoid hyperplasia with eosinophilia is included within the group of hyperplasias because of its historical denomination and its reactive nature, probably as a consequence of an arteriovenous shunt, although usually the lesions do not regress. Pyogenic granuloma, bacillary angiomatosis, intravascular papillary endothelial hyperplasia, and pseudo-Kaposi's sarcoma qualify as vascular hyperplasias because they regress when the stimulus that initiated them is removed. Benign neoplasms form a large group of hemangiomas with distinctive clinicopathologic characteristics, although some of them are of recent description and may produce diagnostic difficulties. We classified cutaneous benign vascular neoplasms according to their cell lineage of differentiation, for example, endothelial, glomus cell, and pericytic differentiation. Subsequent categories are established according to the size of the involved vessels (capillaries, venules and arterioles, or veins and arteries) or the nature of the proliferating vessels (blood or lymphatic vessels). Capillary and cavernous hemangiomas have been the terms classically used to name the most common variants of benign vascular neoplasms (i.e., infantile hemangiomas), but they are not the most appropriate denominations for these lesions. First, these names are not contrasting terms. Furthermore, most of the socalled "cavernous" hemangiomas are not hemangiomas (neoplasms) at all, but venous malformations. The most important conceptual issue is that, at any point in time, a particular hemangioma has its own histopathologic pattern throughout the depth of the lesion. For these reasons, we classified hemangiomas into superficial and deep categories. Some of the lesions reviewed have been recently described in the literature, and they may histopathologically mimic lesions of Kaposi's sarcoma; these include targetoid hemosiderotic hemangioma, microvenular hemangioma, tufted hemangioma, glomeruloid hemangioma, kaposiform hemangioendothelioma, spindle-cell hemangioendothelioma, and benign lymphangioendothelioma. In each of these lesions, we update and emphasize those clinical and histopathologic features that are helpful for differential diagnosis with lesions of authentic Kaposi's sarcoma in any of its three stages of development (patch, plaque, or nodule).

Hemangiopericytoma: a report of two cases arising on the lip

Hemangiopericytoma is a rare tumour of pericytes; represents 1% of all vasoformative tumours and 15-25% of those which occur in the head and neck. We present two cases of hemangiopericytoma occurring on the lower lip and report the use of cryosurgery to treat the most recent case.

Atypical glomus tumor in the mediastinum: a case report with immunohistochemical and ultrastructural studies

A case is reported of atypical glomus tumor occurring in the posterior inferior mediastinum of a 26-year-old woman complaining of severe back pain. The tumor was composed of atypical small, round tumor cells with scattered mitotic figures. In addition to sheet-like, diffuse proliferation of the tumor cells, some areas of the tumor contained small "glomoid" cells arranged in organoid and hemangiopericytomalike patterns. Immunohistochemically, many tumor cells were positive for muscle-type actins and a few cells were focally positive for desmin. Ultrastructural studies revealed smooth muscle features of tumor cells, that is, pinocytotic vesicles, external laminas, dense plaques, and occasional thin filaments with dense bodies. The patient remained well for 5 years and 4 months after the operation without additional radiation and chemotherapy. The tumor was diagnosed as an atypical, or low-grade malignant, glomus tumor morphologically. It seems important to recognize the presence of this type of tumor in sites other than extremities and to differentiate it from other malignant small, round cell tumors.

Rare pulmonary neoplasms

We reviewed the clinical course and the results of various treatment modalities of 80 patients with rare pulmonary neoplasms, who constituted 0.8% of all patients with primary lung cancer treated at the Mayo Clinic from 1980 through 1990. The 50 male and 30 female patients had a median age of 60 years (range, 20 to 87). The histopathologic types of these rare pulmonary neoplasms were non-Hodgkin's lymphoma (41%), carcinosarcoma (20%), mucoepidermoid carcinoma (15%), malignant fibrous histiocytoma (5%), malignant melanoma (4%), fibrosarcoma (4%), leiomyosarcoma (4%), angiosarcoma (2%), hemangiopericytoma (2%), osteosarcoma (1%), and blastoma (1%). Follow-up was complete in all 80 patients, and the median duration of follow-up was 59 months (range, 15 to 130). Of the 80 patients, 63 (79%) underwent pulmonary resection. Of the other 17 patients, 8 underwent only bronchoscopy for diagnosis, 4 had unresectable disease at thoracotomy, 3 had metastatic disease on initial assessment, and 2 had mediastinal involvement detected on mediastinoscopy. Fifty-four patients (68%) received chemotherapy or radiation treatment (or both). The overall 5-year survival was 39%. The strongest factors that influenced survival were cell type and extent of disease at time of initial examination.

Mast cell density and PGP 9.5-immunostained nerves in angioleiomyoma: their relationship to painful symptoms

Angioleiomyoma is frequently painful and the cause of the pain is unknown. The purpose of this study was to compare the mast cell population and innervation of painful and painless angioleiomyomas. Twenty-four cases of angioleiomyoma were examined; 16 painful and 8 painless cases. Pinacyanol erythrosinate and antibodies to protein gene product (PGP) 9.5 were used to demonstrate mast cells and nerves respectively. PGP 9.5-immunoreactive nerve fibres were found in most of the painful (13/16 cases) and painless lesions (5/8). Mast cells were not seen in half of the painful lesions but were seen in most of the painless lesions (7/8). The median mast cell density was 1.1 cells/mm2 for the painful lesions and 21.9 cells/mm2 for the painless lesions (P = 0.048, Mann-Whitney test). The lower mast cell density in the painful lesions may reflect increased mast cell degranulation. It is proposed that neural and vascular events, similar to those occurring in the triple response to mild cutaneous injury, may produce pain in angioleiomyoma and other painful skin tumours.

Hemangiopericytoma of the hand: a literature review and case study

We present a case of hemangiopericytoma of the hand. We also attempt to differentiate hemangiopericytoma from glomus tumor with a summary of the history and a comprehensive review of the literature demonstrating the malignant character of the neoplasm, and we offer some guidelines for treatment.

Haemangiopericytoma of the orbit

Orbital haemangiopericytomas are ideally managed by complete surgical excision in the first instance. This is frequently not achieved, because difficulty in making the diagnosis preoperatively results in incisional biopsy and the highly vascular nature of the tumour makes complete excision difficult. A series of 12 patients with orbital haemangiopericytoma seen over a 23-year period is presented. The following combination of clinical and radiological features is suggestive of haemangiopericytoma. 1. Painless non-axial proptosis with downward displacement of the globe. 2. Intermittent upper lid swelling. 3. A soft, superiorly located mass with poorly defined borders, especially with a blue hue. 4. A superiorly located, rounded or elongated extraconal mass on CT, isodense with brain, with smooth, well-defined borders and moderate to marked enhancement with the injection of intravenous contrast medium. 5. Significant blush in all three phases of carotid angiography, without prominent arteriovenous shunting. Once haemangiopericytoma is suspected, complete surgical excision is recommended.

Differentiation markers in hemangiopericytoma

Normal pericytes were found to express factor XIIIa (F-XIII) and histocompatibility antigen HLA-DR. These markers were studied in 15 hemangiopericytomas (HPC) and 16 other tumors with an HPC-like pattern. A subpopulation of tumor cells expressing F-XIII and HLA-DR antigens was a constant feature of HPC and supported their pericytic origin. Meningeal HPC did not differ in phenotype from peripheral soft tissue HPC. Most tumors with an HPC-like pattern (including synovial sarcomas, malignant schwannomas, leiomyosarcomas, and liposarcomas) were negative for F-XIII and HLA-DR. Malignant fibrous histiocytomas, however, invariably contained a subpopulation expressing these antigens. Therefore, F-XIII can be considered as a marker of fibrohistiocytic differentiation in HPC. Individual tumor cells in HPC occasionally were positive for factor VIII-related antigen (F-VIII-R-Ag), suggesting that the spectrum of differentiation in HPC may include the endothelial cell line. The differentiation characteristics of HPC support the concept that pericytes are primitive cells that may act as precursors to other mesenchymal cells.

Hemangiopericytoma of the lacrimal sac

Hemangiopericytomas of the orbit are rare tumors with low malignancy potential. To the authors' knowledge, only three previous cases of these tumors occurring in the lacrimal sac have been reported. The authors report a fourth case. Follow-up was obtained on the first reported case, and the patient in that case had a recurrence after 15 years. These tumors should be totally excised and followed for long periods of time.

Glomus tumours of the skin: an immunohistochemical investigation of the expression of marker proteins

Immunohistochemical studies were carried out on cutaneous glomus tumours from 10 patients. The glomus areas in these tumours reacted strongly with anti-smooth muscle (CGA-7), anti-muscle (HHF-35) and anti-vimentin antibodies. Their neural supply was analysed using several nervous tissue markers (anti-neurone specific enolase, anti-S 100, anti-Leu 7, anti-neurofilaments). The results indicate a sprouting and proliferation rather than entrapment of pre-existing nerve fibres.

Soft-tissue and meningeal hemangiopericytomas: an immunohistochemical and ultrastructural study

The debate on the nosologic position of hemangiopericytomas of the meninges has been based mainly on light microscopic and ultrastructural considerations; recent immunohistochemical studies have yielded controversial results. We have used a panel of antibodies to vimentin, desmin, actin, S100 protein, epithelial membrane antigen, cytokeratins, Leu-7, factor VIII-related antigen and type IV collagen to compare the immunophenotype of 10 soft-tissue and seven meningeal hemangiopericytomas. The immunophenotypic profile of these tumors is identical, and differs from that of meningiomas in that epithelial membrane antigen and cytokeratin are not present. The vascular pattern occurring in some meningiomas can simulate true hemangiopericytomas of the meninges. Immunohistochemical studies should allow their distinction in each instance. Meningeal and soft-tissue hemangiopericytomas display similar ultrastructural features.

Glomus tumor originating within a digital nerve

Glomus tumors are thought to arise from specialized cells normally found within the glomus apparatus of the dermal stratum reticularis. We report the unusual occurrence of a glomus tumor from within a peripheral nerve. Previous investigators have suggested that the rare occurrence of glomus tumors in tissue where the glomus apparatus has not been described arise from ectopic glomus cells or differentiate from nonglomus cell sources. Many of the "ectopic" glomus tumors have been found in regions of extensive arteriovenous shunting such as in the digestive system and lung suggesting the presence of glomera at these locations. The finding of a glomus tumor within a peripheral nerve, a region where extensive arteriovenous shunting and glomus bodies have not been described, supports the occasional origin of a glomus tumor from a nonglomus cell source.

Ultrastructural spectrum of hemangiopericytoma: a comparative study of fetal, adult, and neoplastic pericytes

Since ultrastructural examination is often employed to assess controversial soft tissue tumors, it is important to be aware of the range of differentiation assumed by the tumor cells in hemangiopericytomas. For this purpose, 35 examples (10 localized to the central nervous system and 25 located peripherally) were examined ultrastructurally, and, of these, 20 cases were also studied immunohistochemically for the presence of intermediate filaments and muscle-specific actin. Based on cytologic characteristics evident by electron microscopy, tumor cell differentiation was classed as pericytic (32%), myoid (8%), nondescript (48%), fibroblastic (4%), and histiocytic (8%). Vimentin was the only intermediate filament expressed in the normal pericytes of human fetal and adult tissues and in the neoplastic pericytes of all of the hemangiopericytomas. Muscle-specific actin was present in normal pericytes, but only focally in two of the hemangiopericytomas. In various combinations basal lamina-like materials, cytoplasmic processes, cytoplasmic filaments, discrete basal lamina, and poorly formed intercellular junctions were the most frequently noted features of the tumor cells in hemangiopericytomas, whether central or peripheral, and they assist, along with the organizational relationship of tumor cells and capillaries, in distinguishing this lesion from other soft tissue sarcomas.

Haemangiopericytomas of the head and neck: a report of two cases

Haemangiopericytomas are rare tumours derived from the pericyte. Two cases originating in the head and neck are described and the methods of treatment outlined.

Oncocytic glomus tumour: a new variant

A new variant of glomus tumour characterized by oncocytic change is reported. The light and electron microscopy and immunohistological findings are described. This is the first reported case of an oncocytoma of non-epithelial origin.

Ultrastructural study of hemangiomas. 5. Glomus tumor (Masson)

The fine structure of four cases of glomus tumor was described. All of the cases showed a solid type, and the glomus cells were shown to be typical or modified smooth muscle cells. Our conclusion is that the glomus cells are not derived from pericytes, but from smooth muscle cells of vascular part of the glomus, and are thought to be a specialized smooth muscle cell tumor.

Erythropoietin in haemangioblastoma: immunohistochemical and electron microscopy studies

Immunohistochemical studies for erythropoietin were carried out in six capillary haemangioblastomas, three of which were also studied by electron microscopy. The immunohistochemical studies showed that positively stained cells were scattered in the vicinity of capillaries, and that neither endothelial cells nor stromal cells were stained. In their morphology and distribution, the positively stained cells were identical to mast cells as observed by electron microscopy. In one case, erythropoietin was demonstrated in the cyst fluid of the tumour. These findings suggest that mast cells with abundant secreting granules in haemangioblastomas are capable of producing erythropoietin.

Intraoral solitary glomus tumor (glomangioma): case report and literature review

The glomus tumor, or glomangioma, is a benign neoplasm arising from the normal glomus. Glomus tumors of the oral cavity are rare, with only ten cases reported in the literature. We report the light and electron microscopic features of an additional case of glomus tumor of the lip which occurred as a solitary, painless, submucosal mass in a 51-year-old woman. Clinical, diagnostic, and histogenetic aspects are discussed.

Vaginal hemangiopericytoma: a light microscopic and ultrastructural study

A case of a vaginal hemangiopericytoma in a 20-year-old woman was studied by light and electron microscopy. The neoplastic cells had round-to-oval nuclei with one or two nucleoli; fine chromatin; a foamy, cyanophilic cytoplasm; and an increased nuclear cytoplasmic ratio. Light microscopically, the tumor was composed of spindle-shaped or round cells proliferating around vascular spaces. Mitotic figures, necrosis, and hemorrhage were difficult to find. Electron microscopically, the neoplastic cells occurred in clusters, each of which was enclosed by a basal lamina. The cytoplasm contained abundant free ribosomes, flattened elements of rough endoplasmic reticulum, small Golgi apparatus, round or elongated mitochondria, lysosomes, glycogen particles, and sometimes pinocytotic vesicles and bundles of microfilaments with large dense spots. Desmosomes were also seen. In addition, the cytoplasmic process of the benign vascular pericytes was directly in contact with the neoplastic cells which had varying degrees of cytodifferentiation. The neoplastic cells in this lesion are consistent with an origin from pericytes, confirming the findings of this neoplasm when it arose in other sites.

Glomus tumor of the cheek: an immunohistochemical demonstration of actin and myosin

A rare case of a buccal glomus tumor was examined by light and electron microscopy. Histologically, the tumor consisted of various vascular spaces surrounded by masses of epithelioid glomus cells, coexisting with a hemangiomatous proliferation of the vessels. Immunohistochemical stainings revealed that the tumor cells were positive for smooth-muscle actin and myosin, with various intensities of the stainings. The electron microscope invariably showed microfilaments in the tumor cells. The results suggest that the glomus tumor cells have characteristics of the smooth-muscle cell and the tumor has a hamartomatous nature.

Glomus tumors of the hand. Presentation of fourteen cases

The authors report a series of fourteen patients with a glomus tumor in the hand. The major symptoms were excruciating spontaneous pain upon mechanical and thermal stimulation of the tumor. In subungual tumors, a blue discoloration is suggestive of diagnosis; but this was found in only 50 percent of cases. The difficult in correct diagnosis and therefore for complete removal is due to in the location of the tumor. Recurrence may occur in cases of incompletely removed tumor. In three cases, the tumor was submitted to electron microscopic examination which led to a better comprehension of the histogenesis of these tumors.

Hemangiopericytoma of the tongue: report of case

A case of hemangiopericytoma of the tongue is reported. A comprehensive literature review regarding hemangiopericytoma of the tongue has been presented. Only ten cases of hemangiopericytoma of the tongue have been reported in the literature, including the present case, a 29-year-old male.

Ultrastructure of multiple glomus tumor

A multiple glomus tumor was studied by electron microscopy. Glomus cells showed characteristics of modified smooth-muscle cells such as intracytoplasmic myofibrils, pinocytotic vesicles, smooth-muscle dense and attachment bodies, which were surrounded by basal lamina, additionally, an abortive solitary cilium was found in a glomus cell.