We report a rare case of oncocytic renal cell carcinoma (RCC) with tubulopapillary growth in the background of tuberculous end-stage kidney disease. Histology of the renal mass consisted of oncocytic cells forming solid, thin tubules and rare papillae. The tumor had abundant eosinophilic oncocytic cells containing occasional cytoplasmic Mallory body–like hyaline globules and a tiny focus of clear cells with intervening mature fat. Both the oncocytic cells and clear cells were immunoreactive for a-methylacyl-CoA racemase, vimentin, pancytokeratin, and CD10, and negative for transcription factor E3, CD15, human melanoma black 45, and c-kit. Mallory body–like hyaline globules were positive for CAM 5.2 and periodic acid–Schiff with or without diastase. Ultrastructurally, the tumor cells had abundant cytoplasmic mitochondria. The present case is a rare case of oncocytic RCC with tubulopapillary growth pattern. The case is unique in that the tumor was mixed with fat component, which is not common in RCC and thus can lead to misdiagnosis.
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Oncocytic papillary renal cell carcinoma (OPRCC): 2 case report and literature review Yanchen Wang, Lihui Guan, Yaming Liu, Yuxuan Liu, Xiaoyan Guo, Yaofei Sun Frontiers in Oncology.2025;[Epub] CrossRef
BACKGROUND To determine the most effective method for detecting mycobacteria in formalin- fixed paraffin-embedded (FFPE) tissue, we compared the results of Ziehl-Neelsen stain (ZNS) and mycobacterial culture with those of polymerase chain reaction (PCR) and real-time quantitative PCR (RQ-PCR). METHODS We analyzed 54 cases diagnosed as chronic granulomatous inflammation. In all cases, ZNS and nested PCR using three different primers, IS6110, Mpb64 and IS6110/Rpobeta were done. RQ-PCR with the IS6110/Rpobeta primer was done in 51 cases. RESULTS Mycobacteria were identified by ZNS in 15/54 (27.8%) cases. RQ-PCR had the highest sensitivity (80.0%) compared to PCR with IS6110 (73.3%), Mpb64 (60.0%) and IS6110/Rpobeta (73.3%). Specificity was higher in all PCR experiments (79.5-82.1%) than in RQ-PCR (69.4%) experiments.
The false negative rate was lowest for RQ-PCR (20.0%) than for PCR with IS6110 (26.7%), Mpb64 (40.0%) and IS6110/Rpobeta (26.7%). The false positive rate was highest for RQ-PCR (30.6%) compared to PCR with IS6110 (20.5%), Mpb64 (17.9%) and IS6110/Rpobeta (20.5%). CONCLUSIONS RQ-PCR had the highest sensitivity, and the lowest false negative rate, but it also had a higher false positive rate than PCR for detection of mycobacteria in FFPE tissues.
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Clinical Usefulness of PCR for Differential Diagnosis of Tuberculosis and Nontuberculous Mycobacterial Infection in Paraffin-Embedded Lung Tissues Yo Na Kim, Kyoung Min Kim, Ha Na Choi, Ju Hyung Lee, Ho Sung Park, Kyu Yun Jang, Woo Sung Moon, Myoung Jae Kang, Dong Geun Lee, Myoung Ja Chung The Journal of Molecular Diagnostics.2015; 17(5): 597. CrossRef
Usefulness of PCR to Mycobacterium Tuberculous and Nontuberculous Mycobacteria from Paraffin-embedded Tissues Yeon-Il Choi, Hye-Young Kim Korean Journal of Clinical Laboratory Science.2014; 46(2): 47. CrossRef
BACKGROUND Surgical resection of the involved lung for nontuberculous mycobacteria (NTM) has become an important curative therapy. However, there is limited information on the histopathological features of NTM pulmonary disease in Korean patients with NTM infection. METHODS We evaluated 51 specimens from 49 patients who were treated at our referral center from 2002 to 2009. RESULTS Almost all the cases showed bronchiectasis with lymphocytic infiltration. Variable features of granulomatous inflammation were found; well-defined granulomas in the parenchyma (68.6%), pneumonia-like granulomatous lesions (49.0%) and granulomatous inflammation in the bronchial wall (41.2%) were identified. The microscopic findings of cavitary lesions (37.3%) showed that these lesions were composed of granulomas and necrosis. CONCLUSIONS The differentiation of tuberculosis from NTM could not be accurately made based solely on the histological features. However, the airway centered tendency of NTM reflected an airborn etiology, and this could be correlated with the classification according to the radiological findings. In addition, coexisting constitutional lung diseases, and especially bronchiectasis, were suspected to be predisposing conditions for NTM organisms to colonize and progress to true NTM pulmonary disease.
Granuloma is a chronic inflammatory process associated with non-infectious agents or infectious diseases such as tuberculosis. It is well known that AFB staining, which has been used to determine the etiology of the granulomatous inflammation, lacks both sensitivity and specificity. Due to the slow growth rate of most pathogenic mycobacteria, culturing of organisms can take up to eight weeks. It is not uncommon for specific therapy to be delayed, or for an inappropriate treatment be given to patients without mycobacterial infections or with infections caused by atypical mycobacteria. Determination of the causative agent in Papanicolaou stained cytology specimens gives pathologists even more difficulties when only necrotic material has been aspirated from the center of the granuloma. In recent years, the use of a polymerase chain reaction for the amplification of DNA has appeared promising in terms of speed, efficiency, sensitivity, and specificity.
Since a polymerase chain reaction permits the sensitive genetic analysis of small amounts of tissue, it is ideally suited to the genetic analysis of cytologic specimens. A polymerase chain reaction is easily performed on unfixed and unstained cells, however, an analysis of ethanol fixed and Papanicolaou-stained archival smears has also been described. We have recently established a method to detect Mycobacterium tuberculosis organism by a nested polymerase chain reaction with primers in the insertion sequence IS 6110, using cellular digests of ethanol-fixed and Papanicolaou-stained archival specimens aspirated from the lymph nodes, lungs, thyroid, etc. Inhibitors present in Papanicolaou stained material was removed by destaining the slides with 0.5% HCl solution for 10-30 minutes. Eight out of ten cases which have shown the epithelioid granulomas revealed a positive reaction and four out of ten cases which have shown lymphohistiocytic cells in a necrotic background without any evidence of granuloma revealed a positive reaction. This study showed that it was possible to employ a polymerase chain reaction to detect Mycobacterium tuberculosis in Papanicolaou stained archival cytology specimens.
BACKGROUND TB-PCR is a faster and more sensitive method to detect mycobacterium than acid-fast bacilli (AFB) stain, which is laborious and time consuming. We compared the sensitivity and specificity of AFB stain and TB-PCR and examined the possibility of TB-PCR as a confirmative test without AFB stain in the diagnosis of tuberculosis. METHODS We performed Ziehl-Neelsen stain and nested PCR using a commercially available TB-PCR kit amplifying IS6110 sequence in 81 cases of paraffin-embedded tissues diagnosed as chronic granulomatous inflammation. In addition, we evaluated the morphology of granuloma and the presence of caseation necrosis. RESULTS Of the 81 cases studied, 22 (27.2%) and 40 (49.4%) were positive for AFB stain and TB-PCR, respectively. Of 49 cases accompanying caseation necrosis, 19 (38.8%) were AFB stain positive and 37 (75.5%) were TB-PCR positive; a result that is comparable with that of other reports. Of the 22 AFB-positive cases, 2 were TB-PCR negative. CONCLUSION TB-PCR is very helpful for the diagnosis of tuberculosis in routinely processed, formalin-fixed, paraffin-embedded tissue samples. Nevertheless, AFB stain should continue to be performed at the same time.
To obtain a useful method for the identification of mycobacteria in tissue section, we evaluated 118 cases of tuberculosis: 48 pulm onary, 14 lymph nodal and 56 synovial tuberculosis. Seventy nine of these cases underwent the culture study. Sections stained with anti-Mycobacterium bovis were compared with the results of the Zieh1-Neelsen stain and culture. The immunohistochemical stain for Mycobacterium bovis in al examined cases was not any more sensitive than the Zieh1-Neelsen stain(p>0.05). Neverthless, the immunohistochemical stain was a useful method for the localization of mycobacteria because of the striking contrast between its background and the wider dimension of a positive area. Immunoreactive areas demonstrated a few intact mycobacteria showing a positive reaction in the Zieh1-Neelsen stain. In conclusion, double staining method using the immunohischemical stain for Mycobacterium bovis and the Zieh1-Neelsen stain is an efficient technique in oder to confirm the diagnosis of tuberculosis.