Faculty Bibliography

OBJECTIVES/OBJECTIVE:To describe the histologic features that are helpful in the diagnosis of the rare bronchiolar adenomas/ciliated muconodular papillary tumors (BAs/CMPTs) during intraoperative consultation. METHODS:Multi-institutional retrospective review of frozen sections of 18 BAs/CMPTs. RESULTS:In 14 of 18 cases, BA/CMPT was the primary reason for sublobar lung resection, and in 4 cases, BA/CMPT was an incidental finding intraoperatively for resections performed for carcinoma in other lobes. There were 11 proximal-type/classic BAs/CMPTs and 7 distal-type/nonclassic BAs/CMPTs. Only 3 (16.7%) of 18 were correctly diagnosed at the time of frozen section, all of which were proximal type/classic. The remainder were diagnosed as adenocarcinoma (n = 7); invasive mucinous adenocarcinoma (n = 1); non-small cell lung carcinoma (n = 1); cystic mucinous neoplasm, favor adenocarcinoma (either mucinous or colloid type) (n = 1); favor adenocarcinoma, cannot exclude CMPT (n = 1); atypical proliferation (n = 2); mucinous epithelial proliferation (n = 1); and mucous gland adenoma (n = 1). CONCLUSIONS:BA/CMPT can potentially be misdiagnosed as carcinoma during intraoperative consultation. On retrospective review of the frozen sections, the presence of the following may help to avoid misdiagnosis: a mixture of bland ciliated columnar cells, mucinous cells, and, most important, a basal cell layer, as well as a lack of necrosis, significant atypia, and mitoses.

Transcription factor E3-rearranged renal cell carcinoma (TFE3-RCC) has heterogenous morphologic and immunohistochemical (IHC) features.131 pathologists with genitourinary expertise were invited in an online survey containing 23 questions assessing their experience on TFE3-RCC diagnostic work-up.Fifty (38%) participants completed the survey. 46 of 50 participants reported multiple patterns, most commonly papillary pattern (almost always 9/46, 19.5%; frequently 29/46, 63%). Large epithelioid cells with abundant cytoplasm were the most encountered cytologic feature, with either clear (almost always 10/50, 20%; frequently 34/50, 68%) or eosinophilic (almost always 4/49, 8%; frequently 28/49, 57%) cytology. Strong (3+) or diffuse (>75% of tumour cells) nuclear TFE3 IHC expression was considered diagnostic by 13/46 (28%) and 12/47 (26%) participants, respectively. Main TFE3 IHC issues were the low specificity (16/42, 38%), unreliable staining performance (15/42, 36%) and background staining (12/42, 29%). Most preferred IHC assays other than TFE3, cathepsin K and pancytokeratin were melan A (44/50, 88%), HMB45 (43/50, 86%), carbonic anhydrase IX (41/50, 82%) and CK7 (32/50, 64%). Cut-off for positive TFE3 fluorescent in situ hybridisation (FISH) was preferably 10% (9/50, 18%), although significant variation in cut-off values was present. 23/48 (48%) participants required TFE3 FISH testing to confirm TFE3-RCC regardless of the histomorphologic and IHC assessment. 28/50 (56%) participants would request additional molecular studies other than FISH assay in selected cases, whereas 3/50 participants use additional molecular cases in all cases when TFE3-RCC is in the differential.Optimal diagnostic approach on TFE3-RCC is impacted by IHC and/or FISH assay preferences as well as their conflicting interpretation methods.

Background: Mary Mallon was termed Typhoid Mary for her role in spreading typhoid fever in the early 1900s. Dr. Soper identified her as a super spreader based on her occupation as a cook in many households that were afflicted. She was subsequently sentenced to enforced confinement to reduce the risk of her continuing to spread disease, yet her exact toll is not fully determined. Pre-antibiotic era, typhoid fever resulted in ~10% mortality. While Mallon has been implicated in 53 cases of typhoid fever, she was implicated in only 3 deaths. We examined the autopsy records of a hospital within 1 mile of her home in NYC to identify whether any deaths from typhoid fever could be associated with her geographically. We anticipated the challenges raised by limited availability of records, however derived inspiration from John Snow's use of geolocation data to elucidate the mechanism of cholera spreading events.
Design(s): We investigated all autopsy records of a public hospital located within 1 mile of the home of Mary Mallon from 1905-1907, prior to her confinement. We recorded name, age, and district of the deceased. We then investigated death and voting registry records for information on the deceased and newspapers for any obituaries. We derived home/work addresses, ethnicity and ages of the deceased to identify any clusters, and to geolocate in relation to Mallon's home/work addresses in the 3 weeks prior to death.
Result(s): We found 22 patients that died of typhoid fever as follows: 20 M, 2 F, ages 23-47, 9 of Irish ethnicity. We grouped them into 4-week clusters of dates of death and identified 7 clusters. The ages in these clusters more closely approximated each other as compared to the overall group. Socioeconomic information was available in a minority of the group, however their treatment and subsequent death in a public hospital suggested their employment in low earning jobs, similar to Mallon.
Conclusion(s): The relatively low death count attributed to Mallon remains unexplained. The patients that died during the time that Mallon lived in the neighborhood of the hospital raise possibility for an association. Archived public records have provided further information on some of the deceased and delineation of small clusters, however insufficient evidence has been derived yet to make any association. Further efforts are planned to searchother city and hospital records to identify the estimated 2-3 unaccounted deaths that may be associated with Typhoid Mary

Background: Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in the genes encoding polycystin 1 and polycystin 2 (PKD1 and PKD2, respectively), leading to florid cystic change of the renal parenchyma. The incidence of carcinoma associated with ADPKD remains unclear although there are studies to suggest that the incidence may be higher.
Design(s): We queried our department pathology database for surgical specimens with ADPKD from 1990 to 2020. We evaluated these cases for the presence of associated malignant or benign neoplasia, as well as pathological and clinical parameters.
Result(s): The majority of the surgical specimens are kidney explants with a clinical diagnosis of ADPKD and the status of end stage kidney diseases. All specimens showed radiological, gross and microscopic features of ADPKD. Eight of 33 ADPKD patients with kidney resection specimens examined contained a malignant neoplasm, including 2 patients with bilateral malignancy. The types of renal cell carcinoma (RCC) associated with the following types: four cases of clear cell RCC, two cases of papillary RCC, type 2, two cases of unclassified high grade RCC, one case of unclassified low grade, as well as one case of TFE3 translocated RCC. Associated carcinomas ranged in size from less than 1 cm to 12 cm. One case with a concurrent oncocytoma and several cases with associated papillary adenoma were also reported.
Conclusion(s): In this cohort, a wide distribution of renal cell carcinoma subtypes were observed, with clear cell RCC being the most common type. The incidence of associated malignancy (24%) is higher than previously reported by Jilg et al. 2013 (5%), possibly due to differences in patient management or patient populations between the institutions. This case series highlights the high occurrence of carcinoma in APKD nephrectomies suggesting a clinical risk of malignancy in patients with ADPKD. Additionally this case series reports the first case of a TFE3 translocated renal cell carcinoma arising synchronously with a contralateral clear cell renal cell carcinoma in a patient with ADPKD. The heterogeneity of renal carcinoma subtypes within the group (and within contralateral kidneys in one patient with bilateral involvement) suggests that stimuli for tumorigenesis arise at the kidney microenvironment level rather than on the basis of gene mutation alone. Accrual of an expanded cohort of patients is planned to enable confirmation of differences between carcinomas arising in the setting of ADPKD versus those arising in end stage renal disease due to other causes, and in the sporadic setting. Furthermore a role for molecular studies is suggested to evaluate if any of the ADPKD causing mutations (PKD1, PKD2, or other) is associated with the development of carcinoma

Background: Entrapped cells or tubules within the fibrous stroma/central scar (fibrous epithelial cellular component = FECC) of oncocytoma have been previously reported although not to date studied in detail. While benign, the varied features of these cells may at times pose a diagnostic challenge. Although these have been attributed as entrapped tubules of oncocytoma, the underlying nature and differentiation of the fibrous epithelial cellular component (FECC) remains unexplored.
Design(s): We evaluated cases of renal oncocytoma for cellular components in the fibrous stroma ('entrapped tubules') and describe their morphologic variation and immunohistochemical features in comparison to the surrounding oncocytoma.
Result(s): We examined twelve oncocytoma cases with fibrous stroma ('central scar') containing FECC which were evaluated further by immunohistochemical studies, including CD117 and CK7. In select cases, additional immunohistochemical stains were performed depending on the renal tumor differential diagnosis. These included carbonic anhydrase IX (CA-9), 34Be12 and AE1/AE3 in select cases. The fibrous stroma of the oncocytoma ('central scar') was noted to represent from 10% to 50% of the tumor area and while predominantly central also extended peripherally as short septa. FECC was predominantly in the stroma immediately subjacent to the usual oncocytoma component. The architecture varied as tubular, trabecular, to diminutive acini with adjacent single cells and showed mixed pattern in majority. Cytologically the FECC had cleared cytoplasm, and slightly larger and vesicular nuclei than oncocytoma cells. Some cases demonstrated an area of transition between oncocytoma and the fibrous cellular component with trabecular bands containing scattered oncocytic intermingled with clear cells. Immunohistochemical studies showed FECC positive for CK7 and CA-9 and negative for CD117 (CK7 +/ CA- 9 +/CD117 -), whereas oncocytoma cells showed the reverse pattern (CK7 -/ CA-9 -/CD117 +). Immunostains for 34betaE12 and AE1/AE3 performed in a subset of cases showed positive staining of in contrast to the nonreactivity in the oncocytoma. (Figure Presnted)
Conclusion(s): FECC or 'entrapped tubules' likely represents a fibrous stromal component of oncocytoma with different microscopic appearance and immunohistochemical profile. It is important to be aware of the variant histological pattern and immunohistochemical profile of oncocytoma as may pose diagnostic difficulty in limited sampling by core needle biopsy. The clear appearance and narrowed trabecular/ tubular pattern is suggestive of an atrophic/ entrapped tumor component, however its varied immunoprofile also raises question as to whether this represents a different differentiation of tumor in an altered microenvironment