Meningeal Hemangiopericytoma Presenting as Pure Gerstmann Syndrome: A Double Rarity.

Gerstmann syndrome is a neurobehavioral syndrome characterized by four cardinal symptoms: acalculia, agraphia, finger-toe agnosia, and dysgraphia. The syndrome is caused primarily by lesions at the confluence of parietal, temporal, and occipital lobes, but also can involve the middle frontal lobe of the dominant hemisphere. Documented inciting lesions include stroke, tumor, hemorrhage, arteriovenous malformations, and seizures. A meningeal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is a diagnostic challenge due to its resemblance to more common brain tumors like meningioma, with histopathology being the definitive diagnostic test. A 37-year-old male presented to our tertiary center with blurred vision, "not being himself," and "acting funny" for three weeks. On exam, he was found to have a right inferior quadrantanopia, grade II papilledema and demonstrated all four symptoms of Gerstmann syndrome - inability to perform simple calculations (acalculia), or identify his fingers (finger agnosia), could not distinguish his left side from the right (left-right disorientation), nor write out his name (agraphia). Brain imaging showed an extra-axial, highly vascularized 7.6-cm mass compressing the left parietal lobe. He underwent a complete resection of the mass. Postoperatively, he had gradual improvement with complete resolution of agraphia, acalculia, finger agnosia, and left-right disorientation within a week status post-resection. Tumor pathology indicated hemangiopericytoma/solitary fibrous tumor. This case enunciates the enigmatic tetrad of Gerstmann syndrome. Though classically described as a sequela of stroke, the mass effect of the tumor on the parietal lobe may produce the symptoms, which can resolve following resection.

A Case of Transformation of Primary Cutaneous Follicle Center Lymphoma to Diffuse Large B-Cell Lymphoma Involving the Parotid Gland and Cervical Lymph Nodes.

BACKGROUND Transformation of primary cutaneous follicle center lymphoma (PCFCL), a low-grade B-cell non-Hodgkin lymphoma (NHL), into a high-grade NHL is rare with uncertain prognosis and treatment. A case is reported of a 40-year-old man who presented with a scalp mass that was diagnosed histologically as PCFCL. Imaging of the head and neck identified diffuse large B-cell lymphoma (DLBCL) involving the parotid gland and cervical lymph nodes, which responded well to radiation therapy. CASE REPORT A 40-year-old African American man presented with a two-year history of a progressively enlarging scalp mass that measured 10.5×7.1×6.6 cm. Histology showed a low-grade lymphoma with a follicular pattern. Immunohistochemistry was positive for B-cell markers and Bcl-6, consistent with a diagnosis of PCFCL. Computed tomography (CT) identified a 4.9×3.7×3.4 cm mass in the left parotid gland with bilateral cervical lymphadenopathy that had been present for the previous two or three months. The diagnosis of DLBCL was made on histology from a needle biopsy. Treatment began with rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (R-EPOCH) chemotherapy, followed by radiation therapy to the scalp, both sides of the neck, and left parotid gland. At four-month follow-up, combined positron emission tomography (PET) and CT showed only diffuse low-level uptake in the scalp and parotid gland. CONCLUSIONS Transformation of low-grade PCFCL to high-grade DLBCL is rare, and the approach to treatment varies. This case showed a good response to chemotherapy and radiation therapy.

Rupture of an Infected Renal Cyst Secondary to a Renocolic Fistula in Autosomal Dominant Polycystic Kidney Disease.

We present a rare case of retroperitoneal rupture of an infected renal cyst secondary to a renocolic fistula in a patient with autosomal dominant polycystic kidney disease (ADPKD). Intraperitoneal rupture of infected cysts in ADPKD resulting in peritonitis has been described, but to our knowledge, this is the first reported case of retroperitoneal rupture. Cyst infections are a common complication of ADPKD and are difficult to treat, potentially leading to sepsis and death.

Targeting the α4ß2- and α7-Subtypes of Nicotinic Acetylcholine Receptors for Smoking Cessation Medication Development.

Nicotine exerts its reinforcing actions via activating the nicotinic acetylcholine receptors (nAChRs). Among an increasing number of nAChR subtypes, the α4ß2 and α7 nAChRs are the two major ones, accounting for about 95% of the whole nAChR population in brain. Research findings from our own laboratory, together with other reports in the field, suggest critical and differential involvement of the α4ß2 and α7 nAChRs in the process of nicotine dependence and tobacco addiction. Specifically, rat models of nicotine consumption and cue-induced relapse were used to examine the effects of selective antagonism of these two nAChR subtypes on the primary reinforcement of nicotine and the conditioned reinforcing actions of nicotine-associated environmental stimuli (cues). Results demonstrated that blockade of the α4ß2 but not α7 subtype effectively reduced nicotine intake, whereas α7 but not α4ß2 nAChR blockade reversed cue-triggered nicotine relapse behavior. These findings lend support for the continued effort to develop cholinergic agents aiming at the α4ß2 nAChRs for reducing or stopping smoking. However, it is suggested that manipulation of α7 nAChR activity would be a promising target for preventing smoking relapse triggered by exposure to environmental cues.

Upward trend of dapsone-induced methemoglobinemia in renal transplant community
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Dapsone, a sulfone antibiotic, is used for prophylaxis of Pneumocystis jirovecii pneumonia in patients with documented sulfa allergy. Acquired methemoglobinemia caused by dapsone is not uncommon in patients with normal glucose-6-phosphate dehydrogenase (G6PD) levels. Discrepancy between oxygen saturation measured by pulse oximetry and arterial oxygen saturation (SpO2) readings, a phenomenon known as "saturation gap," is noted with cases of methemoglobinemia. Although its prevalence in renal transplant patients is poorly described, there is evidence that its incidence is increasing. Here we describe a case series of 4 patients who were switched from trimethoprim-sulfamethoxazole (TMP-SMX) to dapsone and subsequently developed methemoglobinemia. Symptoms occur at varying methemoglobin levels and are more severe in patients with pre-existing coronary disease or chronic lung disease. Early recognition and cessation of dapsone is imperative, especially in renal transplant.
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