Case Reports in Pathology最新文献

The oncocytic variant of chromophobe renal cell carcinoma (oChRCC) and low-grade oncocytic tumor (LOT) is introduced as new renal disease entity. Both of these tumors are low-grade malignancies consisting of cells with eosinophilic cytoplasm. Distinguishing between eosinophilic variant of chromophobe renal cell carcinoma (eCRCC) and oncocytoma is often a diagnostic challenge in routine surgical pathology. However, oChRCC and LOT might be independent disease entities that might not fit completely into any of these categories. Histologically, these tumors have greater morphological similarity with oncocytoma than with ChRCC. However, immunohistochemically, they exhibit diffuse and dense positivity for CK7 and are negative for CD117. In the present case, we initially had difficulty distinguishing among oncocytoma, eCRCC, and type 2 papillary renal cell carcinoma (2-pRCC). However, after learning about new disease entities such as oChRCC and LOT, we were able to diagnose this tumor.

A mildly diabetic 58-year-old male had traumatic ulceration on the left popliteal fossa, and the lesion progressed to a painful 6 cm deep ulcer. After surgical debridement and skin grafting, ulceration recurred. Pyoderma gangrenosum was clinically diagnosed after the first biopsy, indicating a noninfective ulcer. Immunosuppressive therapy (prednisolone and cyclosporine A) induced complete epithelialization in three months. Four months later, subcutaneous nonulcerated nodules appeared on the anterior area of the left lower leg. Subcutaneous induration progressed and ulceration recurred, so that immunosuppressive therapy continued for one year. Cytomegalovirus (CMV) viremia was detected, and the second biopsy demonstrated CMV inclusions of endothelial and perivascular cells in fibrosing septolobular panniculitis. Cyclosporine A was cancelled, prednisolone was tapered, and ganciclovir started. Viremia soon disappeared, but the lesion progressed to large induration with multiple ulcers measuring up to 3 cm. The third biopsy disclosed infection of Gram-positive mycobacteria, accompanying fat droplet-centered suppurative granulomas without CMV infection. Microbial culture identified Mycobacterium chelonae. Clarithromycin with thermotherapy was effective. A review of the second biopsy confirmed coinfection of CMV and Gram-positive mycobacteria. Immunostaining using a panel of anti-bacterial antibodies visualized the mycobacteria in the lesion. Positive findings were obtained with antibodies to Bacillus Calmette-Guérin, Bacillus cereus, MPT64 (Mycobacterium tuberculosis-specific 24 kDa secretory antigen), LAM (Mycobacterium tuberculosis-related lipoarabinomannan), and PAB (Propionibacterium acnes-specific lipoteichoic acid).

Pleomorphic lung carcinoma is a rare and aggressive neoplasm accounting for <1% of all lung tumors. It is more common in men and consists of spindle and/or giant cells with an epithelial component. In patients with known histories of malignancies at other sites, diagnosis of a new lung lesion may prove challenging with respect to classification as either primary or metastatic disease, especially in cases with overlapping immunohistochemical staining patterns. This was a case of a 67-year-old female with a newly discovered 1.5 cm nodule in her left lower lung lobe. Her past medical history was significant for an intracystic papillary carcinoma of the right breast diagnosed 8 years prior. Histopathologic examination of the new lung lesion revealed highly pleomorphic cells composed predominantly of neoplastic giant cells and atypical mitotic figures, with geographic areas of necrosis. However, no areas reminiscent of intracystic papillary carcinoma or other forms of breast carcinoma were seen. Immunohistochemistry showed that the tumor cells were immunoreactive for GATA3, TTF1, and napsin A and nonimmunoreactive for p40. Therefore, although this index lung tumor did show positivity with GATA3 staining, it was morphologically different from her original intracystic papillary carcinoma of the breast. In addition, intracystic papillary carcinomas are known to rarely metastasize to other organs, and GATA3 staining has been rarely reported in lung carcinomas. In summary, this case typifies the overlapping immunohistochemical staining patterns that may be seen in different tumors and the role of histopathologic morphology in arriving at the correct diagnosis.

The patient is a 78-year-old woman with a popliteal soft tissue mass that was tender to palpation with shooting pain on physical examination. A schwannoma was seen on biopsy with subsequent excision demonstrating a concomitant kappa-restricted plasma cell neoplasm. Follow-up did not show evidence of a systemic plasma cell neoplasm. MRI studies showed no evidence of focal lesions, although PET-CT revealed presence of multiple lytic lesions. The patient is currently being monitored every six months. This case is the first kappa-restricted plasma cell neoplasm reported in association with a schwannoma and the first reported in the extremities.

Plasmablastic lymphoma (PBL) is an aggressive high-grade B cell lymphoma, considered a variant of diffuse large B cell lymphoma with approximately 75% mortality within 6-7 months. We describe an unusual case of PBL arising as a maxillary mass in an HIV-negative, nontransplanted 78-year-old female. Histologic examination revealed a diffuse infiltrate of anaplastic appearing cells exhibiting plasmablastic morphology with an adjacent contiguous infiltrate of mature appearing plasma cells. The PBL and mature plasma cell components both demonstrated an immunophenotype of CD20(-), CD38(+), and CD138(+). The two populations differed by the PBL featuring a high proliferation rate by Ki-67 (~95%) with coexpression of both c-MYC and EBV, while the mature plasma cell component featured a low proliferation rate by Ki-67 (~5%) without coexpression of c-MYC or EBV. Kappa/lambda staining demonstrated lambda light chain restriction involving the PBL, while the mature plasma cell infiltrate revealed kappa light chain restriction. Our findings describe the rare association of PBL with a synchronous distinct population of mature plasma cells exhibiting opposite light chain restriction.

Acinar cystic transformation (ACT), also known as "acinar cell cystadenoma," is a rare and newly recognized benign pancreatic cystic neoplasm. However, its true malignant potential remains unknown. Here, we report a case of ACT with 15-year follow-up. A 10-year-old female initially presented with abdominal pain and was found to have a cystic lesion in the region of pancreatic head on computed tomography scan. She underwent an exploratory laparotomy, and the intraoperative biopsy of the cyst wall showed a true pancreatic cyst without malignancy. Her symptoms subsequently resolved, and she was placed under close ultrasound surveillance. For the next fifteen years, the patient was asymptomatic without any complications and had a successful pregnancy. Surveillance showed the tumor grew in size from 4.2 cm to 6.2 cm in diameter. In the latest five months, she noted occasional abdominal pain. A pylorus-preserving pancreaticoduodenectomy was performed. The resected cystic lesion was multilocular and lined by a single layer of bland epithelium ranging from nondescript flat/cuboidal epithelium to apparent acinar cells which were strongly positive for trypsin, so the final diagnosis was confirmed to be ACT. The prior biopsy was retrospectively reviewed to reveal similar epithelial lining. To the best of our knowledge, this is the longest period of follow-up for ACT to date. Our findings suggest that ACT is a slow-growing neoplasm without malignant transformation after fifteen years. Therefore, we recommend biopsy for histologic diagnosis followed by close ultrasound surveillance without surgical intervention in asymptomatic or young ACT patients.

It is uncommon for extramammary tumors to metastasize to the breast, and very few cases describing metastasis of primary uterine leiomyosarcoma to the breast have been reported. We present the case of a 51-year-old woman diagnosed with metastasis of uterine leiomyosarcoma to the breast diagnosed 10 years ago after hysterectomy. Ultrasonography, mammography, and cytology were used to establish a preliminary diagnosis that was confirmed upon examination of the excised tumor that show a rare soft tissue tumor composed of atypical spindle cells and increased proliferation rate. We discuss the importance of distinguishing between various primary mesenchymal tumors of the breast because of phenotypic overlap and some guidance of the histological criteria for metastasis of leiomyosarcoma, as well as differential diagnosis and surgical treatment.

Hypertrophic gastropathy is a rare idiopathic hyperproliferative disorder which may present as Menetrier's disease (MD) characterized by foveolar hyperplasia in the gastric fundus and body. It is often accompanied by a severe loss of plasma proteins (including albumin) from the altered gastric mucosa. The disease occurs in two forms, a childhood form due to cytomegalovirus infection and an adult form attributed to overexpression of transforming growth factor-alpha (TGF-α). The most common symptoms include epigastric pain with fullness and vomiting and generalized peripheral edema with hypoalbuminemia. We present a case of 75-year-old female presenting with epigastric pain and vomiting. Upper gastrointestinal endoscopy and computed tomography scan revealed an irregular mucosal fold at the body and antrum and thickening of the stomach wall, respectively. Though the endoscopic gastric mucosal biopsy was nonspecific, the patient underwent partial gastrectomy due to clinicoradiological suspicion of carcinoma. On histopathology, the case was reported as hypertrophic gastropathy, consistent with MD. Though there is a strong clinical and radiological suspicion of malignancy in the hypertrophied gastric mucosa, MD should be one of the important differential diagnoses.

Aneurysmal bone cyst (ABC) is a well-characterized benign cystic lesion of the bone with common localization to the medulla of the long bones. Rarely, ABCs may arise within the subperiosteal region, which can be diagnostically challenging for both the radiologist and pathologist due to their aggressive radiologic appearance thus mimicking other malignant neoplasms. Herein, we present a rare case of subperiosteal ABC with prominent soft tissue involvement and florid reactive periosteal ossification and provide a short literature review on subperiosteal ABCs.