Pathological features determining recurrence and radioresistance in cerebral atypical meningioma

We examined recurrence after gross total resection (GTR) or subtotal resection (STR) at St. Michael’s Hospital, Toronto, of 181 cases of atypical meningioma (WHO grade II). In the entire group, Kaplan-Meier survival curves showed that combined necrosis and brain invasion was the feature associated with the worst outcome, followed in order by necrosis, histological variants (clear cell, rhabdoid, and chordoid), high mitotic count, and brain invasion. The highly significant difference between necrosis and brain invasion and necrosis was seen only in patients receiving GTR, and lost in those treated with STR. Adjuvant radiotherapy was associated with worse outcome, more so in patients receiving GTR. In the presence of high mitotic count (defined as >4/10HPF) radiation did not affect recurrence, but necrosis and specially combined necrosis and brain invasion magnified the apparent deleterious effect of adjuvant radiotherapy. In the presence of brain invasion, radiotherapy’s small effect did not reach significance. Since patients were not randomized to adjuvant radiotherapy, these results should not be construed as indicating that this treatment is injurious. It can be stated that in the presence of necrosis and particularly necrosis and brain invasion, but not brain invasion alone, or high mitotic count, atypical meningiomas are more resistant to any possible beneficial effect of radiation in delaying recurrence.LEARNING OBJECTIVESThis presentation will enable the learner to: 1.Describe histological and treatment factors determining recurrence in atypical meningioma.2.List histological factors associated with radioresistance in atypical meningioma.

Lymphoma in Psittacine Birds: A Histological and Immunohistochemical Assessment

In psittacine birds, round cell neoplasms that originate from lymphocytes, plasma cells, histiocytes, or mast cells are sporadic and poorly described. The lack of morphological and immunohistochemical diagnostic criteria or grading schemes make specific diagnoses and prognoses challenging. We assessed cases of psittacine birds diagnosed with round cell neoplasia from 3 North American veterinary diagnostic laboratories to describe the diagnostic features of these tumors. For all cases, demographic data, anatomic distribution, histological features, and immunoreactivity for T (CD3) and B (Pax5 and MUM-1) cell markers were assessed using tissue microarrays and whole slide mounts. Thirty-eight psittacine birds representing 14 species were included. Tumors were mainly infiltrative and multicentric, were composed of homogenous sheets of round to polygonal cells, and commonly presented with a high mitotic count (average 21 mitoses per high-power field). Based on Pax5 immunoreactivity, B-cell lymphoma was most common (19/38 [50%]), and was significantly associated with involvement of the gastrointestinal and urogenital systems. Of the 38 cases, 6 (16%) were consistent with T-cell lymphoma, 3 (8%) with plasma cell tumor, and 3 (8%) were double-reactive for both B- and T-lymphocyte markers. This is the first study to describe morphologic and immunohistochemical features of round cell neoplasia in a large number of psittacine birds, and provides benchmark data for future studies aimed at elucidating the diagnosis and prognosis of these neoplasms. These data also provide useful information about reactivity of commercially available antibodies as lymphocyte markers in tissues of multiple psittacine species.

Primary intratesticular rhabdomyosarcoma in children: a case report and review of the literature

Background The importance of this paper is to help to emphasize the importance of chemotherapy for children with pure intratesticular rhabdomyosarcoma after radical inguinal orchiectomy is done as first treatment of rhabdomyosarcoma. The information provided in this paper about the follow-up outcomes of the patient described in this paper, it highlights that, recurrence and even metastasis of intratesticular rhabdomyosarcoma in children are more likely to occur if surgery it not combined with chemotherapy. Case presentation Herein, we present a 6-year old African male child with a 3 months history of a painless right intratesticular tumour. The tumour was poorly vascularized and was in continuity with the spermatic cord. Pelvic computer tomography (CT) scan showed a heterogeneous mass with well-defined margins without microcalcification and multiple bilateral inguinal enlarged lymph nodes were noticed without pelvic lymphadenopathy. The tumour measured 3.8 × 2.8 × 3.9 cm. The tumour marker panel showed: lactate dehydrogenase of (472 UI/l), alpha-fetoprotein (1.43 UI/ml) and human chorionic gonadotrophin beta (2.9 mUI/ml). Microscopically, the tumour was composed of small to medium size undifferentiated cells. These were oval to spindle, hyperchromatic cells to stromal myxoid degeneration were noted. Tunica albuginea and rete testis both were infiltrated by tumour. The tumour showed high mitotic count which measured 50 mitoses per 10 High Power Field (HPF). The diagnosis of rhabdomyosarcoma (RMS) was confirmed by immunohistochemistry (IHC) testing using myoD antibody which showed strong and diffuse intranuclear staining of the tumour cells. Currently, he is on cyclophosphamide and vincristine chemotherapy regime and his condition has improved much. Conclusions The experience obtained from the index case is crucial for the management of patients with intratesticular rhabdomyosarcoma which should always make sure that radical inguinal orchiectomy is covered by chemotherapy and/or radiotherapy. This will potentially lower the possibilities of recurrence and/or metastasis of the tumour, hence improving the prognosis of the patients. We report the clinical, radiological, and laboratory characteristics as well as the outcome of the patient.

Primary intracranial fibrosarcoma in a southern sea otter Enhydra lutris nereis

Southern sea otters Enhydra lutris nereis, a threatened marine mammal species, face numerous environmental and infectious disease challenges in their native habitat of coastal California, USA. However, there are few published cases describing neoplasia in sea otters despite their relatively long life span when cared for in aquarium settings. An 18 yr old neutered male southern sea otter, born and raised in human care, presented with an acute onset of seizures and dull mentation. Magnetic resonance imaging of the head revealed a large, central brain lesion. After no improvement with treatment, euthanasia was elected due to a poor prognosis. Grossly, a poorly demarcated, granular, tan mass expanded the cranial meninges in the longitudinal fissure at the level of the cruciate sulcus and extended into the underlying gray matter and superficial white matter. Histologically, the mass was composed of spindle cells, forming haphazardly arranged interlacing bundles and herringbone patterns, with a high mitotic count, moderate cellular pleomorphism, and prominent vascularization. Neoplastic cells demonstrated positive immunoreactivity for vimentin and negative immunoreactivity for smooth muscle actin, factor VIII-related antigen, S100, melan-A, E-cadherin, desmin, glial fibrillary acidic protein, and cytokeratin AE1/AE3. Based on gross, histologic, and immunohistochemical findings, the mass was most consistent with a primary intracranial fibrosarcoma (PIF). PIFs are a rare neoplasm in both humans and other animals with few reports in the veterinary literature. This is the first recorded case of a PIF in a sea otter.

Atypical Features Resembling Poorly Differentiated Thyroid Carcinoma Presenting Entirely within a Follicular Adenoma

Poorly differentiated thyroid carcinoma (PDTC) is rare and is usually widely invasive at presentation. Here we present an unusual case with a component meeting diagnostic criteria for PDTC by Turin consensus proposal arising within a follicular adenoma. A 44-year-old female was found to have an incidental right thyroid nodule that was suggestive of follicular neoplasm on FNA. Histological examination of hemithyroidectomy revealed an 11 mm focus with insular growth pattern, alteration in cell morphology, and high mitotic count meeting criteria for PDTC. In addition there were several regions showing trabecular architecture with increased mitotic activity but not meeting criteria for PDTC. The literature for such cases is sparse but suggests much better prognosis than conventional invasive PDTC, although a biological potential for aggressive behaviour may be possible.

Malignant Phylloides Tumor in Pregnancy

Malignant phylloides tumors are exceedingly rare with few cases being reported in pregnancy. We describe the first case ever reported of a malignant phylloides tumor presenting in the first trimester of pregnancy and provide insight into the complexities of management as well as a review of the known literature. An extensive PubMed literature search for “cystosarcoma,” “phylloides,” and “pregnancy” was performed. References of each citation were reviewed. Only six previous cases of phylloides tumor in pregnancy were found, none of which were in the first trimester. Medical records of a patient presenting to our institution at 9 weeks gestation with a malignant phylloides tumor were reviewed. We further provide a review of the current literature of the management of phylloides tumor in pregnancy. A 27-year-old white G2P0SA1 woman with no family history of breast cancer presented with a right breast mass at her first prenatal examination at 9 weeks of pregnancy. Ultrasound confirmed a solid mass measuring 24 mm. Core needle biopsy demonstrated a malignant phylloides tumor. She previously had a fibroadenoma removed from the same breast 7 years previously. The current tumor was excised to clear margins. Histopathological examination revealed a 4-cm fibroepithelial tumor with marked stromal cellularity and a high mitotic count (five to seven mitoses/high-power field), confirming the diagnosis of malignant phylloides tumor. The patient continued her pregnancy without complications. Six other cases of phylloides tumor presenting in pregnancy have been reported in the literature, one of which had bilateral disease. Of these, the average patient age was 32 years (range, 28 to 35 years). The majority of these patients presented in their third trimester (mean, 29 weeks; range, 20 to 36 weeks) and often had large tumors (mean, 15 cm; range, 5 to 21 cm). Four of the seven tumors (57%) required a mastectomy. Previous cases have shown phylloides tumors to present in the third trimester as large masses that require mastectomy. With early detection, malignant phylloides tumors can present in the first trimester of pregnancy at smaller sizes; in these patients, breast-conserving surgery is possible.

Malignant Stromal Tumor Consistent with Fibrosarcoma Arising from Meckel's Diverticulum. Clinicopathological Study of an Incidentally Discovered Tumor and Review of the Literature

The authors report a case of a Meckel's diverticulum mesenchymal tumor incidentally discovered in a 69-year-old woman undergoing laparotomy for an ovarian cyst. Histological examination of the tumor revealed a fasciculated proliferation of spindle cells that proved to be immunoreactive to vimentin only; pleomorphism was mild, necrosis extensive and mitotic count high. Because these features were consistent with those of fibrosarcoma, the tumor was classified in the category of gastrointestinal stromal tumors; more specifically, it was considered malignant for the presence of spread beyond the primary site in the form of peritoneal nodules and for the high mitotic count. We have been able to find only one previously reported case of mesenchymal malignant tumor of Meckel's diverticulum classified as fibrosarcoma among the 199 malignant tumors described in the literature. Based on this personal experience and on the review of the literature concerning malignant tumors of Meckel's diverticulum, we discuss both the rarity of these tumors and the importance of removing Meckel's diverticulum every time it is found during laparotomy.