Hemangiopericytomatous Pattern Research Articles

Phosphaturic mesenchymal tumor: Clinicopathological features with outcomes in 10 patients with review of literature.

Phosphaturic mesenchymal tumors (PMTs) are rare mesenchymal tumors, associated with long-standing, non-specific but often debilitating symptoms in the affected patients. These tumors display characteristic histopathological features and in case, identified timely, can be a boon for patients, given an excision is completely curative. To evaluate the clinical and histopathological features of 10 PMTs, diagnosed at our institution, along with clinical outcomes in those patients. This was a retrospective study, wherein 10 PMTs, diagnosed from January 2013 to July 2022, were included. The average age at the time of diagnosis was 40 years with an M:F ratio of 4:1. Clinical features included lumps, weakness, bone pain, difficulty in moving and walking, and pathologic fractures. The biochemical analysis showed normal serum calcium levels (average = 9.5 mg/dL), with low serum phosphorus (average = 2.2 mg/dL) and raised serum fibroblast growth factor 23 (FGF23) levels, in all the cases, wherever available. On histopathology, all tumors showed cells arranged in a hemangiopericytomatous pattern, including oval to short spindle forms. Multinucleate giant cells were present in nine tumors, and characteristic "grungy calcifications" was observed in eight tumors. Prominent pseudo cystic spaces were seen in eight tumors. A significant number of mitotic figures and tumor necrosis were not seen in any tumor. In five cases where follow-up was available, there was complete resolution of symptoms post-resection with no recurrence or metastasis. All those patients were free of disease until the last follow-up. This constitutes the first largest comprehensive study on these rare tumors from our country. PMTs can be diagnosed based on certain histopathological features and correlation with clinicoradiological and biochemical findings. These are invariably benign neoplasms. Patients are relieved of their debilitating symptoms after adequate surgical tumor resection. Therefore, their correct and timely diagnosis is crucial.

Malignant giant solitary fibrous tumour of the mediastinum; masquerading Triton tumour

BackgroundMalignant Solitary fibrous tumour (SFT) is an uncommon mesenchymal tumour with aggressive clinical behaviour as compared to its benign counterpart. There are only a handful of reports of extra-pleural malignant SFT arising from the mediastinum.Case presentationA 68-year-old male, presented with a history of cough and breathlessness for 2 weeks. Computed tomography (CT) scan revealed a large 11.6 × 11.3x18cm anterior mediastinal mass with extension to right hemithorax. The patient underwent excision of the mass after a biopsy confirmation of mesenchymal tumour. Histological examination of resection specimen revealed a spindle cell tumour with hypo and hypercellular areas, arranged in fascicular, focal storiform and hemangio-pericytomatous vasculature pattern. Moderate to marked nuclear atypia, frequent mitosis and areas of necrosis were noted. On immunohistochemistry (IHC), the tumour cells were positive for CD34, Bcl2, MIC2 (dot-like) and focally for S100 and Desmin. Although, the possibility of a malignant peripheral nerve sheath tumour with heterologous rhadomyosarcomatous differentiation (Triton tumour) was considered, however IHC for STAT6 confirmed it to be a malignant SFT. The patient developed recurrence within 1 year after surgery and despite multi-modality treatment (Re-excision, Chemotherapy and Radiotherapy) succumbed within 14 months from point of presentation.ConclusionMalignant SFT is a rare aggressive tumour that should be considered as a differential diagnosis in the mediastinum and a broad panel of IHC markers including STAT6 may be required to confirm the diagnosis.

Leiomyosarcoma of inferior vena cava with intracardiac extension presenting as Budd-Chiari syndrome: Report of a rare case

Primary leiomyosarcoma of vascular origin is a rare malignant smooth muscle tumor. This report describes a case of primary leiomyosarcoma of the inferior vena cava (IVC) in a 52-year-old male who presented with complaints of abdominal pain, chest pain, and bilateral lower limb swelling for 4 months. Imaging of the chest and abdomen revealed a mass in the IVC extending into right atrium, heterogeneous enhancement of liver, hepatosplenomegaly, and ascites. Histopathological examination showed a malignant spindle cell tumor with cells arranged in fascicular and hemangiopericytomatous pattern. Immunohistochemistry for smooth muscle actin and desmin confirmed smooth muscle origin of the tumor. Recognition of this tumor in this rare location and Budd-Chiari syndrome-like presentation is imperative for proper management of the patient.

Abdominal monophasic synovial sarcoma is a morphological and immunohistochemical mimic of gastrointestinal stromal tumour.

Synovial sarcomas may arise within retroperitoneal or pelvic tissues or, more rarely, within the luminal gastrointestinal tract. This case series aims to demonstrate how such primary abdominal synovial sarcomas may particularly mimic gastrointestinal stromal tumour (GIST) on both morphological and immunohistochemical grounds. Four cases of primary abdominal synovial sarcoma were reviewed morphologically and with immunohistochemistry, fluorescence in-situ hybridization with an SS18 break-apart probe, and KIT/PDGFRA mutation analysis. The four patients comprised two males and two females, with a median age of 42 years (range: 17-59 years). Two synovial sarcomas arose within the stomach, one within the small-intestine mesentery, and the fourth within the retroperitoneum. All four tumours showed only a monophasic spindle cell component in the tissues available for review. All four tumours showed DOG1 immunopositivity, and three coexpressed CD117. Three tested cases did not show activating KIT or PDGFRA mutations, whereas all four cases showed chromosomal rearrangement of SS18. A diagnosis of synovial sarcoma should be considered particularly if an abdominal spindle cell neoplasm shows a haemangiopericytomatous pattern and diffuse CD99 and CD56 immunopositivity. A confident distinction between abdominal synovial sarcoma and GIST requires KIT/PDGFRA mutation analyses and specific molecular testing for synovial sarcoma.

12. Primary mediastinal synovial sarcoma

Synovial sarcoma predominantly occurs in the soft tissues of the extremities. Primary synovial sarcoma in the mediastinum is exceedingly rare and only a few cases have been reported, most of which were in the posterior mediastinum. This is a case of a 68 year old lady with a previous history of left sided mediastinal tumour (MPNST) who presented with increasing shortness of breath. CT scan revealed a posterior mediastinal mass. Microscopically, the tumour was composed of hypercellular spindle cells arranged predominantly in sheets, short fascicles with focal herring bone and hemangiopericytomatous pattern. The cells were oval to spindle with overlapping nuclei, inconspicuous nucleoli with scant indistinct cytoplasm. The stroma shows patchy areas of thick intercellular collagen and plentiful scattered thick and thin walled staghorn vessels. No definite epithelial elements were seen. The tumour cells showed strong diffuse staining for vimentin and CD99. Weak, patchy positivity for EMA and BCL-2 were noted. This is further confirmed by FISH which showed rearrangement of SS18 (18q11.2) in a significant proportion of tumour nuclei. Synovial sarcoma predominantly occurs in the soft tissues of the extremities. Primary synovial sarcoma in the mediastinum is exceedingly rare and only a few cases have been reported, most of which were in the posterior mediastinum. This is a case of a 68 year old lady with a previous history of left sided mediastinal tumour (MPNST) who presented with increasing shortness of breath. CT scan revealed a posterior mediastinal mass. Microscopically, the tumour was composed of hypercellular spindle cells arranged predominantly in sheets, short fascicles with focal herring bone and hemangiopericytomatous pattern. The cells were oval to spindle with overlapping nuclei, inconspicuous nucleoli with scant indistinct cytoplasm. The stroma shows patchy areas of thick intercellular collagen and plentiful scattered thick and thin walled staghorn vessels. No definite epithelial elements were seen. The tumour cells showed strong diffuse staining for vimentin and CD99. Weak, patchy positivity for EMA and BCL-2 were noted. This is further confirmed by FISH which showed rearrangement of SS18 (18q11.2) in a significant proportion of tumour nuclei.

Solitary fibrous tumour of the thyroid: a case report

A 37-year-old female presented with a painless slow growing neck mass. The right thyroid lobe was excised including a discrete spindle cell lesion. Microscopically, the lesion was composed of bland spindle cells arranged in storiform, fascicular and ‘patternless’ areas with alternating zones of hyper- and hypocellularity. Additionally, keloid-like collagen and a haemangiopericytomatous vascular pattern were also noted. The lesion had an infiltrative growth pattern with entrapped normal thyroid follicles both in the centre and at the periphery of the lesion. There was no marked nuclear pleomorphism or necrosis. Immunohistochemistry studies showed the lesional cells to be positive for vimentin, CD34, CD99, BCL2 and STAT6 and negative for AE1/AE3, CAM5.2 and TTF1. The morphology and immunoprofile confirmed a diagnosis of a solitary fibrous tumour.

Primary mesenchymal tumor of adrenal

Primary mesenchymal tumor of adrenal is very rare. We present a case of adrenal mesenchymal tumor. A 48-year-old Chinese woman was admitted to hospital presenting symptom of distension and pain at the left upper quadrant of the abdomen for one year. Computed tomography images showed a circumscribed mass at the left adrenal region which measured about 9 × 12cm. Macroscopy, a nodular mass in the left adrenal gland with an capsule was 13 × 10 × 8cm in size, and the cut surface of which was soft, grayish white and yellow, with cystic change and hemorrhage in some areas, a little cortex at the periphery remained. Histopathology, compact short spindle, oval and polygonal tumour cells arranged in sheets, partly, in haemangiopericytomatous pattern. The tumour cells were uniform with ovoid pale-staining nuclei and inconspicucous nucleoli. Cytoplasm was sparse and cell borders were indistinct. Mitotic figures were about 2–3/10 HPF.Focally, necrosis and degeneration could be found. Immunohistochemical staining revealed the tumor cells were positive for CD117, vimentin, CD99, Bcl-2 and EMA. While Keratin, Dog-1, CD34, α-inhibin and calretinin <i>et al</i>. were negative. The patient is survival now 4.5 years after adrenalectomy without any therapy, but there has been a local recurrence since last year.

Myopericytoma of the external auditory canal and tragus

Myopericytoma is a relatively recently described skin and soft tissue tumour that demonstrates perivascular myoid cell or pericytic differentiation. Whilst the range of anatomical locations has expanded to include visceral locations, head and neck myopericytomas are rarely documented. There have been no previous reports of aural myopericytoma. This paper reports the clinicopathological features of a biopsy-proven, slow-growing, 20 × 20 mm, polypoid myopericytoma that involved the external auditory canal and tragus in an 18-year-old woman. Excision was curative. Heightened clinicopathological awareness of the expanding anatomical distribution of myopericytoma is critical to its diagnosis when it presents in unusual and novel locations. Myopericytoma should be added to the range of external auditory canal neoplasms, especially those characterised by an admixture

Solitary myofibroma of the sigmoid colon: case report and review of the literature

A 58-year-old woman presented with a solitary myofibroma that arose in the sigmoid colon. Computed tomography revealed a highly enhanced intramural mass (1.3-cm maximum diameter) in the proximal sigmoid colon. Histologically, the tumor exhibited a biphasic growth pattern, which comprised haphazardly arranged, interwoven fascicles of plump, myoid-appearing spindle cells with elongated nuclei and abundant eosinophilic cytoplasm, and more cellular areas of primitive-appearing polygonal cells that were arranged in a hemangiopericytomatous pattern. The tumor cells were positive for smooth muscle actin (SMA), and negative for desmin, h-caldesmon, CD34, cytokeratin, S100 protein, and CD117. The Ki-67 labeling index was not high (up to 7%). Based on these histologic and immunohistochemical features, our patient was diagnosed with a myofibroma of the sigmoid colon. The presence of solitary myofibroma in the intestine of an adult requires attention to avoid misdiagnosis as a more aggressive mesenchymal tumor.Virtual SlidesThe virtual silde(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2096403796957687

Intra-abdominal primary monophasic synovial sarcoma with hemangiopericytoma-like areas

We report a case of retroperitoneal intra-abdominal primary monophasic synovial sarcoma (SS) with hemangiopericytomatous (HPC) pattern in a 25-year-old male arising from the triangular ligament on the superior surface of liver encasing the inferior vena cava (IVC) and masquerading as a hepatic tumor. A large heterogeneously enhancing, well defined, lobulated, exophytic lesion was seen involving segment VIII of the liver with foci of calcification in the periphery. A biopsy, followed by total resection of the tumor, showed a spindle cell sarcoma with HPC pattern, which was consistent with monophasic SS on histology and immunohistochemistry. The unusual clinical presentation, radiology, pathology, and differential diagnosis will be discussed in detail.

Dumb-bell shaped poorly differentiated pelvic synovial sarcoma with molecular confirmation: A rare presentation of an uncommon disease entity

Pelvic localization of synovial sarcoma is a rare phenomenon and to the best of our knowledge its presentation as a large "dumb-bell"-shaped abdomino-pelvic mass showing extension to the thigh has never been reported in the literature. We report a case of a young adult presenting with retention of urine and was found to have a large abdomino-pelvic mass causing bony destruction and compression of pelvic viscera. A biopsy revealed a cellular tumor composed of spindle to oval cells arranged in a hemangiopericytomatous pattern. Histopathology was suggestive of poorly differentiated synovial sarcoma. Immunohistochemistry (IHC) was positive for vimentin, CD 99, Bcl2, Mic2 and focally for EMA and negative for CD 34, CK, desmin, synaptophysin, and WT1. Due to equivocal IHC findings molecular analysis was done which confirmed the diagnosis as synovial sarcoma.

A Primary Pulmonary Glomus Tumor: A Case Report and Review of the Literature

A case of a glomus tumor originating from the lung is reported. A 43-year-old female had undergone resection of a right lung tumor following a clinical diagnosis of carcinoid, sclerosing hemangioma, or other sarcoma. Histologically, the tumor comprised uniform small round to oval cells with centrally located nucleus, a clear cytoplasm, and apparent cell borders. The tumor also showed a focally hemangiopericytomatous pattern with irregularly branching or dilated vessels. Electron microscopy revealed smooth muscle differentiation of the tumor cells. Immunostaining further revealed that the tumor cells expressed smooth muscle actin, h-caldesmon, muscle specific actin (HHF-35), but not cytokeratin, epithelial membrane antigen, synaptophysin, or chromogranin A. Based on these findings, a diagnosis of primary pulmonary glomus tumor was established. Glomus tumors of the lung are very rare and only 21 cases have been reported to date. The histological features of the present tumor and the relevant literature are discussed.

Mesenchymal chondrosarcoma of the cervical spine: A case report.

Mesenchymal chondrosarcoma (MCS) is a rare tumour accounting for less than 1% of all chondrosarcomas. We report here, the case of a 30-year-old female who presented with neck pain, weakness and tingling and numbness starting on the right side and later involving all four limbs. MRI revealed an ill-defined neoplastic lesion showing specks of calcification and arising from the right half of C2 and C3 cervical vertebrae. Microscopy showed an admixture of well differentiated cartilage showing focal calcification and spindly cell areas having a hemangiopericytomatous pattern.

Characteristic endobronchial ultrasound image of hemangiopericytoma/solitary fibrous tumor

Hemangiopericytomatous pattern is characteristic of hemangiopericytoma/solitary fibrous tumor (HPC/SFT) and certain histological features might indicate a malignant potential, but the behavior of HPC/SFT is unpredictable. Endobronchial ultrasound (EBUS) is a useful diagnostic device in that the ultrasonographic image can be viewed and the EBUS-transbronchial needle aspiration can obtain a biopsied sample. We herein report a patient undergoing multiple surgical resections of recurrent HPC/SFT. A 74-year-old man had undergone right upper lobectomy for HPC/SFT 15 years ago. He received a partial resection of the left lung and a resection of the anterior mediastinal mass for its recurrences 13 years and six years ago, respectively. He had also undergone surgery for gastric carcinoma two years ago. He then presented with a tumor measuring 3 x 4 cm in the subcarinal area. Preoperative EBUS revealed a tumor with abundant thin-walled vessel-like structures, which was consistent with HPC/SFT. The tumor was completely resected and was finally diagnosed as low-grade malignant HPC/SFT.

Clinicopathological and immunohistochemical analysis of sclerosing stromal tumours of the ovary

Sclerosing stromal tumours (SST) of the ovary are rare, benign tumours. SSTs are usually hormone inactive and tend to occur in the second and third decades of life. The most common clinical symptom is menstrual irregularity. Fourteen women diagnosed with SST of the ovary were included in this study. Tumour samples were collected, embedded in paraffin and stained with haematoxylin and eosin, periodic acid-Schiff (PAS), and PAS with digestion, as well as immunohistochemically for vimentin, smooth muscle actin, desmin, CD 99, inhibin-α and the oestrogen and progesterone receptor. The age of the patients ranged from 16 to 54 years (mean age 25.2 years). The tumours ranged in size from 6 to 21 cm (mean 10.5 cm). Macroscopically, eight tumours were solid and six were solid and cystic. All SSTs were well circumscribed with pseudolobule formation. Spindle-shaped fibroblast-like cells and vacuolated theca-like cells were prominent. Blood vessels exhibited a hemangiopericytomatous pattern and boomerang-like features. Immunohistochemical results were as follows: vimentin, 14/14 cases positive; smooth muscle actin, 14/14 cases positive; desmin, 14/14 cases positive; CD 99, 4/14 cases positive; inhibin-α, 14/14 cases positive; oestrogen receptor, 0/14 cases positive; progesterone receptor, 2/14 cases positive. The characteristic histopathological features we observed in our study are usually adequate for the diagnosis of SSTs. Although inhibin-α, CD 99 and desmin staining may be a useful and reliable tool for SST diagnosis in problematic cases, an immunohistochemical panel will not discriminate from other tumours in the sex cord-stromal group.

Clinicopathologic analysis of 4 cases of primary renal synovial sarcoma

Primary renal synovial sarcoma is rare and might be misdiagnosed as another renal tumor. This study demonstrates the clinicopathologic and immunohistochemical features, differential diagnosis, and prognosis of such tumors. Histologic slides and clinical data were reviewed for 4 patients with primary renal synovial sarcoma and immunohistochemical staining was performed. Molecular analysis was performed on 2 cases to demonstrate the presence of the SYT-SSX gene fusion transcripts by reverse transcriptase polymerase chain reaction (RT-PCR). The patients were 2 women and 2 men aged from 32 to 48 years. The tumors were 10.0-15.0 cm in diameter, grey-white and solid, and hemorrhage or necrosis was observed. Microscopically, the tumors consisted of mitotically active, monomorphic plump spindle cells with indistinct cell borders growing in short, intersecting fascicles. Hypocellular myxoid areas and a prominent hemangiopericytomatous pattern were present in all cases. The average mitotic rate was 5-8 mitoses/10 high-power fields. Hemorrhage and tumor necrosis were easily found. Scattered small cysts lined with flat, cuboidal, or hobnailed epithelia were found in 3 cases. Tumor cells are immunoreactive for Vimentin (4/4), Bcl-2 (4/4), CD99 (4/4), and CD56 (3/4), and focally for EMA (3/4) and Cytokeratin (3/4). SYT-SSX1 gene fusion was detected in the 2 cases in which RT-PCR analysis was performed. One patient had tumor metastasis to the lung 6 months after surgery and died 5 months later. Multiple metastasis to the liver occurred in one patient and the patient died 13 months after the initial surgery. The other 2 patients had tumors recur at 8 and 15 months and died at 18 and 21 months, respectively, after the initial operation. Primary renal synovial sarcoma is rare, with poor prognosis, characterized by SYT-SSX gene fusion, and needs to be differentiated from other renal sarcomas.

Tumor fibroso solitario de la vulva

Solitary fibrous tumour (SFT) is a rare mesenchymal tumour initially identified in the pleura, but that can be present in virtually all regions. Isolated cases arising in the female genital tract have been described in recent years. We report the case of a woman aged 35 who presented with a vulvar tumour, which was resected. On pathological examination the tumour measured 20mm in diameter and showed typical features of SFT, consisting of spindle cell proliferation without atypia, alternating with hyper- and hypo-cellular areas, presence of abundant collagen and with a vascular hemangiopericytomatous pattern. Immunohistochemistry was strongly positive for CD34 and bcl-2 and negative for S-100 and actin. SFT shows aggressive behaviour in approximately 25% of cases and should always be considered a potentially malignant tumour, and requires a clinical follow-up. Therefore, the identification and differentiation from other lesions with similar features in the female genital area is essential.

Undifferentiated sarcoma: does it exist? A clinicopathologic study of 7 pediatric cases and review of literature

Undifferentiated sarcomas are primitive mesenchymal tumors that cannot be classified among standardized histopathologic entities. Whether they represent a homogeneous group with common histogenesis and clinical behavior or comprise a variety of tumors able to differentiate along specific maturative lineages is still debated. To identify prognostic and histogenetic markers, we analyzed 7 undifferentiated sarcomas (4 in the trunk and 3 in the extremities). Mean patient age was 7.5 years, and mean follow-up was 18 months. Two clinicopathologic subtypes emerged from this study. Four primitive mesenchymal undifferentiated sarcomas arose mainly on the trunk and very proximal extremities, had an aggressive clinical course with poor outcome (3 deaths from disease, 1 with persistent disease), and displayed sheets of oval cells, with bland nuclei. Three spindle cell undifferentiated sarcomas arose on the extremities, had a favorable outcome, and showed elongated spindle cells with areas of primitive fibrosarcoma. All were negative for epithelial membrane antigen, cytokeratins, CD34, smooth muscle actin, desmin,Myf4, and HMB45 and showed nuclear staining for INI. Focal staining for S100 and CD99 was found in 3 and 4, respectively. Among stem cell markers, CD117 was positive in 3 cases (1 primitive, 2 spindle), nestin in 5 cases (4 primitive, 1 spindle), and CD105-stained tumor cells lining newly formed vascular spaces in 4 cases (1 primitive, 3 spindle). Survivin was weakly expressed in 6 cases and reflected low levels of mRNA (median survivin/GAPDH ratio, 1.096). Cytogenetic analysis revealed nonspecific translocations in 3 tumors. No translocations associated with Ewing sarcoma, synovial sarcoma, or alveolar rhabdomyosarcoma were found. In summary, primitive undifferentiated sarcomas occur in the trunk, behave aggressively, and express nestin. Spindle cell undifferentiated sarcomas occur in extremities, have a favorable outcome, resemble fibrosarcomas, and have similarly low survivin levels and display CD105-positive vascular spaces, which may represent an early hemangiopericytomatous pattern.

Primary endobronchial synovial sarcoma confirmed by SYT-SSX1 fusion gene transcript by reverse transcriptase polymerase chain reaction

Primary sarcomas of lung are rare compared to metastatic sarcomas. Herein, we report a rare case of primary pulmonary synovial sarcoma with polypoid endobronchial growth in a 35-year-old lady who presented with cough and dyspnea. A malignant pulmonary tumor was suspected and left pneumonectomy was performed. Grossly, a non-encapsulated polypoidal endobronchial tumor measuring 6 cm in greatest diameter, with a solid, tan-white cut surface was identified. Microscopically, tumor was characterized by a proliferation of oval to spindle-shaped cells arranged in sheets and fascicles. Focal hemangiopericytomatous pattern was noted. Immunohistochemically, tumor cells were positive for vimentin, BCL-2, MIC-2 and calponin and focally positive for pancytokeratin and epithelial membrane antigen. A subsequent molecular analysis performed using reverse transcriptase-polymerase chain reaction with RNA extracted from paraffin-embedded tissue, revealed SYT/SSX1 fusion gene which confirmed the diagnosis of synovial sarcoma. The utility of immunohistochemistry and molecular techniques in diagnosis of such a rare case is stressed and the relevant literature is discussed.

Synovial sarcoma of the kidney

The renal parenchyma is a rare site of origin for primary synovial sarcoma (SS). The present study describes the clinicopathologic, immunohistochemical, and molecular analysis of 7 cases of SS occurring in the kidney. There were 5 female and 2 male patients, with an age range of 15 to 46 years. They presented with solitary renal masses ranging in size from 10.0 cm to 17.0 cm in greatest dimension. Radical nephrectomy was performed in all cases. On gross examination, tumors were large, partially necrotic, and were seen to contain smooth-walled cysts in 4 cases. Histologically, the tumors were characterized by monomorphic spindle cells with indistinct cell borders arranged in intersecting nodular foci with hypocellular myxoid areas, together with a prominent hemangiopericytomatous pattern. The cysts were lined by hobnailed cells with eosinophilic cytoplasm. Immunohistochemically, BCL-2 was positive in all 6 cases in which it was performed, followed by vimentin (4/5 cases), MIC2 (CD99; 2/5 cases), calponin (2/2 cases), and epithelial membrane antigen (1/4 cases). Stains for cytokeratin and CD34 were consistently negative. Reverse transcription-polymerase chain reaction (RT-PCR) using RNA extracted from formalin-fixed paraffin-embedded tissues was carried out in 4 cases and SYT-SSX fusion gene transcript, which is the diagnostic hallmark of SS, was detected. Two patients developed pulmonary metastasis and died 6 and 12 months after diagnosis, respectively. This series of cases is distinct in terms of its morphological spectrum and confirmation by molecular technique.