Atypical Presentation of Tenosynovial Giant Cell Tumor on the Hallucal Flexor Tendon Sheath: A Case Report.

Tenosynovial giant cell tumor (TGCT) is a rare type of neoplasm that may be locally aggressive but is most often benign and can be divided into two subtypes: localized and diffuse. It tends to develop in the joints, bursae, and tendon sheaths primarily in the digits of the hand and less commonly in the forefoot. This soft-tissue mass has many possible differential diagnoses, including lipoma, ganglion cyst, plantar fibroma, and various sarcomas; surgical excision is usually indicated to reach a definitive diagnosis and rule out malignancy. We report a rare case of a 30-year-old woman with atypical plantar hallucal pain and a palpable mass on the plantar lateral aspect of the left hallux. Surgical excision and histopathologic evaluation confirmed a TGCT of the left hallucal flexor tendon sheath. Although it bears clinical resemblance to several other soft-tissue masses, TGCT has numerous pathognomonic features evident with advanced imaging and histologic analysis that help the physician obtain an accurate diagnosis and proceed with appropriate treatment.

Improved Graft Function following Desensitization of Anti-AT1R and Autoantibodies in a Heart Transplant Recipient Negative for Donor-Specific Antibodies with Antibody-Mediated Rejection: A Case Report.

HLA donor-specific antibodies (DSAs) pre and post transplant increase the risk of antibody-mediated rejection (AMR) and lead to poor graft survival. Increasing data exist to support the involvement of non-HLA antibodies in triggering an immunological response. The development of non-HLA antibodies specific for AT1R is associated with poor clinical outcomes in orthotopic heart transplant recipients. This case presents an investigation of non-HLA antibodies in a 56-year-old female heart transplant recipient diagnosed with AMR in the absence of DSAs.

The Hunt for Lymph Nodes: Is Total Submission of Standard-Template and Extended-Template Pelvic Lymph Node Dissections Necessary for Detecting Metastatic Prostate Cancer?

CONTEXT.­: There are no consensus guidelines on submission of pelvic lymph node dissection (PLND) specimens for radical prostatectomies. Complete submission is only performed by a minority of laboratories. Our institution has been following this practice for standard-template and extended-template PLND. OBJECTIVE.­: To investigate the utility of total submission of PLND specimens for prostate cancer and understand its impact on patients and the laboratory. DESIGN.­: Retrospective study examining 733 cases of radical prostatectomies with PLND performed at our institution. Reports and slides with positive lymph nodes (LNs) were reviewed. Data on LN yield, cassette usage, and impact of submission of remaining fat after dissection of grossly identifiable LNs were assessed. RESULTS.­: Most cases involved submission of extra cassettes for remaining fat (97.5%, n = 697 of 715). Extended PLND yielded a higher mean number of total and positive LNs versus standard PLND (P < .001). However, extended PLND required significantly more cassettes for remaining fat (mean, 8; range, 0-44). There was poor correlation between number of cassettes submitted for PLND with total and positive LN yield and between remaining fat with LN yield. Most positive LNs were grossly identified (88.5%, n = 139 of 157) and were typically larger than those not. Only 4 cases (0.6%, n = 4 of 697) would have been understaged without complete submission of PLND. CONCLUSIONS.­: Total submission of PLND increases detection of metastasis and LN yield yet increases workload significantly with only minimal patient management impact. Hence, we recommend that meticulous gross identification and submission of all LNs be pursued without the need to submit the remaining fat of PLND.

Serous cavity metastasis: Evaluation of unknown primary.

Malignant effusions can occur in patients with neoplasia. Once a metastatic diagnosis is confirmed, the primary site of origin of malignancy needs to be ascertained. This task can be challenging without a prior history of malignancy. In some patients their effusion may be the initial presentation of an underlying malignancy. Metastases usually present with a dual population of mesothelial and malignant cells. Combining cytomorphologic examination with ancillary testing such as immunocytochemistry can help identify the origin of the foreign malignant cell population. Helpful architectural clues include a single cell pattern, solid cell ball pattern, single file arrangement, papillary formation, psammoma bodies and background mucin. Useful cellular features include the presence of signet ring cells, small cells, pleomorphic and multinucleated giant cells, squamous cells, spindle cells and pigmentation. Rarely, despite an extensive work-up the primary site of origin for a malignant effusion may remain unresolved. This review article will be incorporated finally as one of the chapters in CMAS (CytoJournal Monograph/Atlas Series) #2. It is modified slightly from the chapter by the initial authors in the first edition of Cytopathologic Diagnosis of Serous Fluids.

Pilomatrixoma and its Imitators.

Introduction: Pilomatrixomas are benign neoplasms derived from hair follicle matrix cells. They are among the most common soft tissue head and neck tumors of childhood. Pilomatrixomas are typically isolated, slow-growing, firm, nontender masses that are adherent to the epidermis but mobile in the subcutaneous plane. This clinical presentation is so characteristic that many experienced surgeons will excise suspected pilomatrixomas without prior imaging. We reviewed the results of this approach to determine whether physical examination alone differentiates pilomatrixomas from other similar soft tissue lesions of the pediatric head and neck. Methods: Computerized review of all pilomatrixomas over a 20-year period in a single academic pediatric otolaryngology practice. Results: 18 patients presented to our pediatric otolaryngology practice between 2001 and 2021 with historical and physical findings consistent with pilomatrixoma. Of the 18 patients, 7 were male and 11 were female. Ages ranged from 1.5 to 14 years, with a mean of 7.5 years. Most of the lesions (12) were located in the head and face, while the rest (6) were found in the neck. All patients were treated with complete surgical excision. Pathology confirmed pilomatrixoma in 15 patients. The remaining 3 children were found to have an epidermal inclusion cyst, a ruptured trichilemmal cyst, and a giant molluscum contagiosum lesion, respectively. One additional patient presented with a small lesion of the auricular helix that was thought to be a dermoid cyst, but proved to be a pilomatrixoma on histologic examination. Discussion: As pilomatrixomas are common and have a very characteristic presentation, surgical excision without prior diagnostic imaging will lead to correct treatment in the majority of cases. High resolution ultrasonography can help to confirm the diagnosis preoperatively, but is not definitive in large case series. Most of the cystic lesions that imitate pilomatrixoma will ultimately require surgical excision.

PD-L1 Positivity Associated With Presence of Tertiary Lymphoid Structures and High-Stage Disease in Upper Tract Urothelial Carcinoma.

OBJECTIVES: Persistent antigen exposure leads to the accumulation of lymphocytes and subsequent tertiary lymphoid structures (TLS). We investigated the relationship of tumor microenvironment (TME) with respect to programmed death ligand 1 (PD-L1), its receptor programmed death 1 (PD-1), and TLS in upper tract urothelial carcinoma (UTUC) cases and compared them with UTUC associated with urothelial bladder carcinoma (UTUC-BCa). METHODS: We retrospectively identified 72 patients with UTUC. Representative slides were reviewed, and TLS were counted. Immunohistochemical stains for PD-1 and PD-L1 were performed. PD-1-positive lymphocytes were counted and H-score for PD-L1-positive membranous staining was determined. RESULTS: PD-L1 expression in the tumor was present in 55.1% of the UTUC cases. Higher stage was associated with increased PD-L1 expression (P = .035). TLS were present in 33.3% and their presence was significantly associated with PD-L1 positivity (P = .024). This association remained significant after adjustment for UTUC-BCa. TLS were also associated with a greater number of infiltrating PD-1-positive lymphocytes (P = .013). CONCLUSIONS: This study is one of the first comparative studies of the TME in UTUC and UTUC-BCa. PD-L1 is expressed in a subset of UTUC and is associated with TLS. The presence of TLS is an inherent characteristic of UTUC and not secondary to the presence of BCa.

PD-L1 detection in histology specimens and matched pleural fluid cell blocks of patients with NSCLC.

BACKGROUND AND OBJECTIVE: Analysis of programmed death ligand-1 (PD-L1) in tumour samples is necessary to identify candidates for anti-PD-L1/PD-L1 therapy. Because PD-L1 is evaluated by immunohistochemistry (IHC), an adequate amount of tumour tissue is a prerequisite for PD-L1 testing. To examine whether pleural fluid might be an alternative to biopsy/resection specimens for IHC evaluation of PD-L1 in patients with non-small cell lung carcinoma (NSCLC), we compared PD-L1 by IHC between histological specimens and matched pleural fluid. METHODS: A retrospective cohort study of patients with NSCLC who underwent core biopsy of a lung mass/surgical resection with PD-L1 IHC and had a pleural fluid cell block (CB) available for PD-L1 staining was conducted. PD-L1 was categorized as negative (PD-L1 in <1% of tumour cells), moderately positive (PD-L1 in ≥1% to <50%), strongly positive (PD-L1 ≥ 50) or inadequate for PD-L1 testing (<100 tumour cells in the CB). Weighted Cohen's kappa was calculated to evaluate the agreement between PD-L1 on biopsy/resection specimen and pleural fluid for variables with more than two categories. RESULTS: Of the 115 patients included in this study, 82 (71.3%) had at least 100 tumour cells and were included in the analysis. Of these, 80 (97.6%) had adenocarcinoma. For PD-L1 of histological specimens versus pleural fluid categorized as negative, moderately positive or strongly positive, the weighted kappa statistic was 0.76 (95% CI: 0.64-0.88), and the concordance was 0.78 (95% CI: 0.68-0.86). CONCLUSION: Correlation and concordance are high between PD-L1 in histological specimens and matched pleural fluid. Evaluation of PD-L1 in pleural fluid should be considered in patients unable to undergo histological biopsies.

PD-L1 Expression Reveals Significant Association With Squamous Differentiation in Upper Tract Urothelial Carcinoma.

OBJECTIVES: Limited literature is available on the tumor microenvironment (TM) of upper tract urothelial carcinoma (UTUC). This study comprehensively reviews programmed death 1 receptor (PD-1)-positive and CD8+ tumor-infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) expression on tumor epithelium (TE). METHODS: Seventy-two nephroureterectomy specimens were analyzed for PD-L1, PD-1, and CD8. One percent or more tumor and lymphohistiocyte PD-L1 expression was considered positive. TIL density by H&E was scored semiquantitatively from 0 to 3, and CD8+ and PD-1+ TILs were quantified in hotspots. RESULTS: Of the cases, 37.5% demonstrated PD-L1+ on TE. PD-L1+ TE showed an association with pathologic stage (P = .01), squamous differentiation (SqD) (P < .001), TILs by H&E (P = .02), PD-1+ peritumoral TILs (P = .01), and PD-L1+ peritumoral lymphohistiocytes (P = .002). Finally, there was a significant difference in PD-1+ peritumoral TILs in cases with SqD vs no SqD (P = .03). CONCLUSIONS: Aggressive UTUC is associated with a distinct TM. Furthermore, TM of UTUC-SqD was distinctly different from those with no SqD, warranting study in a larger cohort.

The use of cytological material in melanoma for programmed death ligand 1 immunostaining.

OBJECTIVE: Interest in immune therapies has exploded since the 2014 approval of first-generation programmed cell death 1 blocking antibodies for use in advanced melanoma. Clinical trials have focused primarily on histological material as the gold standard for evaluating programmed death ligand 1 (PD-L1) by immunoperoxidase (IPOX) studies. Studies validating the use of cytological specimens in the assessment of PD-L1 by IPOX staining are needed to optimise tissue utilisation in complementary diagnostic testing. METHODS: Twenty-three melanoma surgical biopsies (SBx) with an IPOX stain for PD-L1 clone 28-8, and a corresponding cytological specimen from the same patient, adequate for PD-L1 evaluation, were selected. Cell-transfer cell blocks (CBs) and conventional CBs were used to perform PD-L1 testing. Tumour proportion scores (TPS) were generated and the results were correlated with the corresponding SBx. RESULTS: Overall agreement (OA) using a ≥1% TPS cut-off for SBx compared to CB was 88.9%, positive percent agreement (PPA) was 87.5%, and negative percent agreement (NPA) was 100%, OA using a ≥5% TPS cut-off was 55.6%, PPA was 42.9%, and NPA was 100%. SBx compared to cell-transfer CB using a ≥1% TPS cut-off had an OA of 65.2%, a PPA of 55.6%, and a NPA of 100%, while a ≥5% TPS cut-off generated an OA of 52.2%, a PPA of 35.7%, and a NPA of 77.8%. CONCLUSION: Our results demonstrate that cytological material, particularly conventional CB, is a viable alternative for evaluating PD-L1 in melanoma cases and suggest that a lower threshold (≥1%) may be beneficial when evaluating cytological material.

The usefulness of various cytologic specimen preparations for PD-L1 immunostaining in non-small cell lung carcinoma.

INTRODUCTION: Evaluation of programmed cell death ligand-1 (PD-L1) on formalin-fixed paraffin-embedded (FFPE) histologic specimens is required for immunotherapy with pembrolizumab in non-small cell lung carcinoma (NSCLC). A significant percent of patients may be diagnosed on cytology samples alone; however, FFPE tissue may not always be available. Here, we evaluated the feasibility of PD-L1 staining on a variety of cytologic preparations including conventional cell blocks (CB), cell-transfer cell blocks (CTCB), and direct smears. MATERIALS AND METHODS: We identified 30 NSCLC cytology cases that had PD-L1 status evaluated on a concurrent core needle biopsy. Papanicolaou-stained smears (PS) were reviewed and a moderately cellular smear was selected per case to prepare a CTCB. CTCB, CB, and PS (when available) were stained with PD-L1 22C3 and tumor proportion scores (TPS) were compared across all preparations with the concurrent core biopsies. RESULTS: Concordance of PD-L1 positivity in CB and PS versus core biopsy was high, 80% (12 of 15) and 94.4% (17 of 18), respectively. CTCB versus core biopsy concordance was lower in comparison, 62% (13 of 21) for PD-L1 positivity. Overall, TPS was lower in CTCB compared with CB and PS. Among the 3 preparations, CTCB and CB sections were easier to interpret as PS displayed various artifactual staining patterns. CONCLUSIONS: In summary, our study demonstrates that CB and PS preparations are suitable surrogates for histologic FFPE tissue for determining PD-L1 status in NSCLC patients. CTCBs, on the other hand, show high discordance and are not optimal specimens. Pre-analytic factors in unconventional cytology preparations may need optimization and negative results should be interpreted with caution.

Malignant Mixed Epithelial and Stromal Tumor of the Kidney With 2 Simultaneous Renal Carcinomas in a Male Patient: Case Report and Review of the Literature.

The majority of mixed epithelial and stromal tumors (MEST) of the kidney are benign entities found in female patients. Malignant MEST of the kidney is an extremely rare entity that often behaves clinically similar to an undifferentiated sarcoma. We report a case of a malignant MEST with synchronous papillary and clear cell renal cell carcinomas (RCCs) in a 61-year-old Caucasian man who presented with an incidental finding of a left renal mass on workup for back pain. The patient underwent a left radical nephrectomy, with histopathology confirming a malignant MEST, intimately associated papillary RCC, and separate adjacent focus of clear cell RCC.

Staged management of giant bilateral perinephric adipocytic neoplasms.

We present a patient with giant bilateral perinephric masses favored to represent liposarcoma preoperatively. Bilateral renal involvement posed a clinical challenge; careful histologic assessment and surgical planning allowed preservation of renal function.

Atypical retiform hemangioendothelioma arising in a patient with Milroy disease: a case report and review of the literature.

Retiform hemangioendothelioma (RH) is a rare vascular neoplasm with a high rate of local recurrence and low metastatic potential. We describe an unusual case of RH in a 45-year-old patient with Milroy disease, with a prominent solid component diffusely involving a chronic lymphedematous leg. This case is consistent with the postulated relationship between lymphedema and vascular neoplasms developing as a result of local immune dysfunction, and highlights the need to closely monitor patients with Milroy disease for pathologic changes. Our case highlights a unique example of RH with atypical features. There are several noteworthy unusual clinical and histologic findings including diffuse involvement of an entire limb, solid component with cytologic atypia, D2-40 expression, and first-time-reported association with Milroy disease. Given the atypical histologic presentation of cytologic atypia, solid areas and atypical immunohistochemical profile with D2-40 positivity, this case could cause diagnostic difficulty, especially in the setting of such a broad clinical differential.

Teratogenic potential in cultures optimized for oligodendrocyte development from mouse embryonic stem cells.

We describe a rapid and efficient 5-step program of defined factors for the genesis of brain myelin-forming oligodendrocytes (OLs) from embryonic stem cells (ESCs). The OLs emerge on the same time frame in vitro as seen in vivo. Factors promoting neural induction (retinoids, noggin) are required, while exogenous Sonic hedgehog is not. In contrast we were unable to generate OLs by trans-differentiation of ethically neutral mesenchymal stem cells, indicating a requirement for cis-differentiation via neural ectoderm for OL genesis. In the ESC-derived cultures, our optimized protocol generated a mixed population with 49% O4(+), Olig2(+) OL lineage cells. These cultures also retained pluripotential markers including Oct4, and an analysis of embryoid body formation in vitro, and allogeneic grafts in vivo, revealed that the ESC-derived cultures also retained teratogenic cells. The frequency of embryoid body formation from terminal differentiated OL cultures was 0.001%, 100-fold lower than that from ESCs. Our results provide the first quantitative measurement of teratogenicity in ESC-derived, exhaustively differentiated allogeneic grafts, and demonstrate the unequivocal need to purify ESC-derived cells in order to generate a safe population for regenerative therapy.