Burkholderia pseudomallei: abscess in an unusual site

Melioidosis is an infection caused by Burkholderia pseudomallei. It is an important human pathogen in tropical area. The clinical manifestations are protean and multisystem involvement. We report an unusual case of melioidosis with abscess at root of mesentery in an elderly, non-insulin dependent diabetic Thai women. She presented with prolonged fever and chronic abdominal pain. The early clinical diagnosis was carcinomatous mass with peritonitis. Diagnosis of melioidosis arose from the surgical finding and pus culture. Treatment with surgical drainage and ceftazidime followed by co-trimoxazole plus doxycycline had a good clinical outcome.     

Giant lobulated seborrheic keratosis at an unusual site

Seborrheic Keratoses(SK) are common benign skin tumors of elderly occurring commonly on face, scalp, extremities, chest, back with genital and perianal sites being rare. Lesions are usually few millimeters to several centimeters, reaching pendulous proportions in areas of constant friction, especially in obese individuals. Though malignant transformation is rare, it is reported in irritated lesions, especially in flexures. An unusual case of giant lobulated seborrheic keratoses occurring in perianal area, without any evidence of malignancy on histopathology, in an otherwise healthy obese female is reported here.     

Isolation of Neissseria meningitidis from an unusual site

A 59-year-old post-menopausal lady who had returned from a pilgrimage to Mecca about a month earlier presented with a three days' history of profuse vaginal discharge. Neissseria meningitidis was isolated from high vaginal swab specimens taken from her on 2 occasions, five days apart. Her symptoms disappeared without treatment after two weeks. We conclude that although the organism may have been a colonizer, it is possible that it was responsible for the self-limiting genital infection in this patient.     

Intraluminal renal metastasis from a rectal adenocarcinoma: an unusual site

Primary adenocarcinoma of the urinary tract are uncommon. But secondary involvement of pyelocalyceal system by metastasis of colorectal origin is rare. We report a case of late rectal metastasis with renal pelvis growth presenting as a pyonephrosis. This study emphasizes the relevance of cytokeratin 7 and 20 immunostaining in such differential diagnosis.     

Mesenchymal chondrosarcoma of the thyroid -- a rare tumour at an unusual site

We describe the light microscopic, immunohistochemical and ultrastructural features of the first case in the literature of a primary mesenchymal chondrosarcoma (MC) of the thyroid and discuss its differential diagnosis at unusual extraskeletal sites. A nodular lesion of the thyroid with no evidence of extrathyroid disease showed the bimorphic pattern and haemangiopericytoma-like areas typical of MC. In the undifferentiated areas, the cells were CD99 positive/CD117 negative, while the stroma showed focal positivity for alpha-inhibin. In spite of its rarity, it is important to diagnose primary mesenchymal chondrosarcoma in a parenchymatous organ such as the thyroid because its biological behaviour may be different from that of tumours of similar morphology and complete resection is the treatment of choice. The patient is free of disease nearly 66 months after its first presentation. Cytogenetic and immunohistological markers may play important roles in diagnosis of this lesion in future, especially with limited tissue samplings; however, for the present a thorough sampling of the tumour remains the best diagnostic strategy.     

A case of gallstone ileus with an unusual impaction site and spontaneous evacuation

Gallstone ileus is an unusual cause of colonic obstruction. The formation of a fistula between the gall bladder and the bowel wall may allow a gallstone to enter the intestinal tract. Plain abdominal films, abdominal ultrasound and abdominal computed tomography aid in the diagnosis. Although surgery is the treatment of choice in cases of colonic gallstone ileus, colonoscopic removal of the impacted stone should be attempted. We describe the case of an 85-year-old man who presented with symptoms and signs of large bowel obstruction. Diagnostic evaluation revealed a large gallstone impacted in the sigmoid colon, which is a rather unusual impaction site. Despite our efforts we could not extract the stone endoscopically, mainly due to its large size. Yet, despite its large size, the stone was spontaneously evacuated a few hours later.     

Recognition of IgG-derived peptides by a human IgM with an unusual combining site

A monoclonal immunoglobulin (Ig)M cryoglobulin (Mez) with interesting binding behaviour was isolated from a Waldenström's macroglobulinemia (WM) patient. It demonstrated very strong binding to peptides derived from the sequences of human IgG. However, when tested for binding to intact IgG, this antibody (Ab) did not show any rheumatoid factor (RF) activity. We propose several nonexclusive structural interpretations of the Mez‐binding propensities, based on the orientations and solvent accessibilities of ligand residues and the nature of the Ab‐binding site. To further characterize the structural features of Mez‐peptide binding, IgG‐derived octapeptides were docked into the Mez fragment variable (Fv)‐binding site, revealing additional reasons for Mez‐binding selectivity based on the interactions of the docked peptides with the Mez Fv. The problem was also approached from an immunological perspective. Comparisons of Mez variable region of the light chain (VL)/variable region of the heavy chain (VH) sequences with those of human germlines and known IgM RFs allowed us to provide a possible outline tracing the structural and functional origins of the Mez IgM. Coupled with examinations of interactions in docked complexes, this analysis led us to propose that the potential for RF activity, demonstrated through Mez binding to IgG‐derived peptides, was owing to the inherent sequence and structure of the Mez IgM, rather than to somatic mutations. Thus, Mez IgM may occupy an intermediate niche between IgMs with and without RF activity.     

Pitfalls in the diagnosis of epithelioid sarcoma presenting in an unusual site: a case report

The cytologic appearance of epithelioid sarcoma in fine-needle aspiration biopsy cytology (FNABC) smears has not been extensively described. We report a case of epithelioid sarcoma in a 55-year-old male who presented with nodular swellings in the abdominal wall and scrotum. The scrotal swelling was subsequently demonstrated to arise from the vas deferens. We highlight the cytomorphologic, immunocytochemical, and histopathologic features of this rare lesion in an unusual site, with particular emphasis on the dilemma encountered in the cytodiagnosis of this lesion.     

Medullary thyroid carcinoma metastatic to the pituitary gland: an unusual site of metastasis

We present a case of metastatic medullary thyroid carcinoma involving the pituitary gland of a 23-year-old woman with multiple endocrine neoplasia type 2b who presented with diabetes insipidus and visual loss. The diagnostic features, including cytomorphology and immunohistochemistry, used to differentiate pituitary adenoma from metastatic medullary carcinoma are discussed. Pituitary metastases and tumor-to-tumor metastases in this region are also highlighted.     

Monotypic epithelioid angiomyolipoma of the adrenal gland: an unusual site for a rare extrarenal tumor

Epithelioid angiomyolipoma (AML) is an uncommon renal mesenchymal tumor with malignant potential and is frequently associated with tuberous sclerosis. Extrarenal AMLs are rare, and to the best of our knowledge, this is the first reported case of a primary monotypic epithelioid AML of adrenal gland in a patient without evidence of tuberous sclerosis. The patient is a 42-year old man who presented with retroperitoneal hemorrhage resulting from spontaneous rupture of adrenal mass. Histologically, the tumor showed a prominent component of epithelioid smooth muscle cells with slightly pleomorphic nuclei, sometimes with prominent nucleoli and eosinophilic cytoplasm resembling oncocytic tumors. Epithelioid cells were positive for melanoma (HMB45 and positive MelanA) and smooth muscle markers (α-smooth muscle–specific actin), but not for epithelial markers (cytokeratin, EMA). Differential diagnosis from renal cell carcinoma, adrenal gland carcinoma, and metastatic carcinoma is often challenging because of its epithelioid morphology. Because primary and secondary malignant tumors are much more common and aggressive neoplasms, establishing the correct diagnosis has important therapeutic and prognostic implications.     

Microevolution of Burkholderia pseudomallei during an Acute Infection

We used whole-genome sequencing to evaluate 69 independent colonies of Burkholderia pseudomallei isolated from seven body sites of a patient with acute disseminated melioidosis. Fourteen closely related genotypes were found, providing evidence for the rapid in vivo diversification of B. pseudomallei after inoculation and systemic spread.     

Burkholderia glumae infection in an infant with chronic granulomatous disease

An 8-month-old boy developed a necrotic lung mass from which Burkholderia glumae was recovered, leading to the diagnosis of chronic granulomatous disease (CGD). While other Burkholderia species have been identified as important pathogens in persons with CGD, B. glumae has not been previously reported to cause human infection.