Papillary thyroid carcinoma with nodular fasciitis-like stroma and ß-catenin mutations should be renamed papillary thyroid carcinoma with desmoid-type fibromatosis.

Various histological variants of papillary thyroid carcinoma have been reported, some with clinical implications, some with peculiar, sometimes misleading morphologies. One of these rare and poorly characterized variants is papillary thyroid carcinoma with nodular fasciitis-like stroma, of which fewer than 30 cases have been documented, mostly as isolated reports. It is a dual tumor comprising a malignant epithelial proliferation that harbors typical features of conventional papillary thyroid carcinoma, admixed with a prominent mesenchymal proliferation resembling nodular fasciitis or fibromatosis. Thus, the terms papillary thyroid carcinoma with nodular fasciitis-like stroma and papillary thyroid carcinoma with fibromatosis-like stroma are used interchangeably; however, the former term suggests a self-limited and regressing disease, whereas the latter one suggests a recurrent and potentially aggressive one. Better genetic and ultrastructural characterization could lead to more appropriate terminology and management. We performed detailed clinicopathological and molecular analyses of two cases of PTC with prominent mesenchymal proliferation that developed in the thyroid gland of two male patients aged 34 and 48. In both cases, the epithelial component harbored a heterozygous somatic activating BRAF mutation (p.V600E). Also, in both cases, the mesenchymal component showed typical aberrant nuclear and cytoplasmic immunoreactivity for ß-catenin and harbored a heterozygous somatic activating mutation in the corresponding CTNNB1 gene (p.S45P). This mutation has never been reported in thyroid stroma; in other tissues, it is typical of desmoid-type fibromatosis rather than nodular fasciitis-like stroma. We therefore propose that in cases of papillary thyroid carcinoma with a prominent mesenchymal component, mutations in CTNNB1 should be sought; when they are present, the term 'papillary thyroid carcinoma with desmoid-type fibromatosis' should be used. As the mesenchymal component of these tumors is not expected to concentrate radioactive iodine, special considerations apply to clinical evaluation and follow-up, which should be brought to the attention of the treating specialist.

Reticular Perineurioma of the Hand: Diagnosis and Treatment of a Rare Case of Hand Mass.

Reticular perineurioma is a rare and recently delineated morphologic variant of benign perineurioma of skin and soft tissues. Because of its nonspecific gross appearance, varying histologic patterns, and potential range of cellularity, perineurioma of the hand is likely to be confused with more commonly encountered tumor or tumor-like conditions such as schwannoma, neurofibroma, fibromyxoid tumors, and giant tumor of tendon sheath. We report the case of a 20-year-old woman who presented with a slowly growing mass of the hand, which was eventually identified as a reticular perineurioma.

Diagnostic Value of the CD103+CD4+/CD4+ Ratio to Differentiate Sarcoidosis from Other Causes of Lymphocytic Alveolitis.

BACKGROUND: The CD103 integrin is present on CD4+ lymphocytes of the bronchial mucosa, but not on peripheral blood CD4+ lymphocytes. It has been hypothesized that CD4+ lymphocytes in pulmonary sarcoidosis originate from redistribution from the peripheral blood to the lung, and therefore do not bear the CD103 integrin. Some data suggest that a low CD103+ percentage among bronchoalveolar lavage fluid (BALF) CD4+ lymphocytes discriminates between sarcoidosis and other diagnoses. OBJECTIVE: To determine the diagnostic value of BALF CD103+ to identify sarcoidosis among other causes of alveolar lymphocytosis in a large retrospective case series. METHODS: Among 391 consecutive bronchoalveolar lavages performed at our institution and analyzed by flow cytometry, we identified 207 cases, which were grouped into nine diagnostic categories: sarcoidosis, tuberculosis, non-tuberculous infections, hypersensitivity pneumonitis, non-specific interstitial pneumonia, organizing pneumonia, drug-induced lung diseases, other interstitial lung diseases (ILDs), and other diagnoses. To assess the discriminative value of the CD103+CD4+/CD4+ ratio to distinguish sarcoidosis from other entities, areas under ROC curves (AUC) were calculated. RESULTS: Sarcoidosis patients (n = 53) had significantly lower CD103+CD4+/CD4+ ratios than patients in other diagnostic categories. The AUC was 62% for sarcoidosis compared to all other diagnoses, and 69% for sarcoidosis compared to other ILDs. When combining CD103+CD4+/CD4+ and CD4+/CD8+ ratios, the AUC increased to 76 and 78%, respectively. When applying previously published cut-offs to our population, the AUC varied between 54 and 73%. CONCLUSIONS: The CD103+CD4+/CD4+ ratio does not accurately discriminate between sarcoidosis and other causes of lymphocytic alveolitis, neither alone nor in combination with the CD4+/CD8+ ratio, and is not a powerful marker for the diagnosis of sarcoidosis.

Mitotic figure counts are significantly overestimated in resection specimens of invasive breast carcinomas.

Several authors have demonstrated an increased number of mitotic figures in breast cancer resection specimen when compared with biopsy material. This has been ascribed to a sampling artifact where biopsies are (i) either too small to allow formal mitotic figure counting or (ii) not necessarily taken form the proliferating tumor periphery. Herein, we propose a different explanation for this phenomenon. Biopsy and resection material of 52 invasive ductal carcinomas was studied. We counted mitotic figures in 10 representative high power fields and quantified MIB-1 immunohistochemistry by visual estimation, counting and image analysis. We found that mitotic figures were elevated by more than three-fold on average in resection specimen over biopsy material from the same tumors (20±6 vs 6±2 mitoses per 10 high power fields, P=0.008), and that this resulted in a relative diminution of post-metaphase figures (anaphase/telophase), which made up 7% of all mitotic figures in biopsies but only 3% in resection specimen (P<0.005). At the same time, the percentages of MIB-1 immunostained tumor cells among total tumor cells were comparable in biopsy and resection material, irrespective of the mode of MIB-1 quantification. Finally, we found no association between the size of the biopsy material and the relative increase of mitotic figures in resection specimen. We propose that the increase in mitotic figures in resection specimen and the significant shift towards metaphase figures is not due to a sampling artifact, but reflects ongoing cell cycle activity in the resected tumor tissue due to fixation delay. The dwindling energy supply will eventually arrest tumor cells in metaphase, where they are readily identified by the diagnostic pathologist. Taken together, we suggest that the rapidly fixed biopsy material better represents true tumor biology and should be privileged as predictive marker of putative response to cytotoxic chemotherapy.

Immunoregulation of Dendritic Cell Subsets by Inhibitory Receptors in Urothelial Cancer.

Blockade of inhibitory receptors (IRs) overexpressed by T cells can activate antitumor immune responses, resulting in the most promising therapeutic approaches, particularly in bladder cancer, currently able to extend patient survival. Thanks to their ability to cross-present antigens to T cells, dendritic cells (DCs) are an immune cell population that plays a central role in the generation of effective antitumor T-cell responses. While IR function and expression have been investigated in T cells, very few data are available for DCs. Therefore, we analyzed whether DCs express IRs that can decrease their functions. To this end, we investigated several IRs (PD-1, CTLA-4, BTLA, TIM-3, and CD160) in circulating CD1c+ DCs, CD141+ DCs, and plasmacytoid DCs from healthy donors and patients with urothelial cancer (UCa). Different DC subsets expressed BTLA and TIM-3 but not other IRs. More importantly, BTLA and TIM-3 were significantly upregulated in DCs from blood of UCa patients. Locally, bladder tumor-infiltrating DCs also overexpressed BTLA and TIM-3 compared to DCs from paired nontumoral tissue. Finally, in vitro functional experiments showed that ligand-mediated engagement of BTLA and TIM-3 receptors significantly reduced the secretion of effector cytokines by DC subpopulations. Our findings demonstrate that UCa induces local and systemic overexpression of BTLA and TIM-3 by DCs that may result in their functional inhibition, highlighting these receptors as potential targets for UCa treatment. PATIENT SUMMARY: We investigated the expression and function of a panel of inhibitory receptors in dendritic cells (DCs), an immune cell subpopulation critical in initiation of protective immune responses, among patients with urothelial carcinoma. We found high expression of BTLA and TIM-3 by blood and tumor DCs, which could potentially mediate decreased DC function. The results suggest that BTLA and TIM-3 might be new targets for urothelial carcinoma treatment.

Altered Prostasin (CAP1/Prss8) Expression Favors Inflammation and Tissue Remodeling in DSS-induced Colitis.

BACKGROUND: Inflammatory bowel diseases (IBD) including ulcerative colitis and Crohn's disease are diseases with impaired epithelial barrier function. We aimed to investigate whether mutated prostasin and thus, reduced colonic epithelial sodium channel activity predisposes to develop an experimentally dextran sodium sulfate (DSS)-induced colitis. METHODS: Wildtype, heterozygous (fr/+), and homozygous (fr/fr) prostasin-mutant rats were treated 7 days with DSS followed by 7 days of recovery and analyzed with respect to histology, clinicopathological parameters, inflammatory marker mRNA transcript expression, and sodium transporter protein expression. RESULTS: In this study, a more detailed analysis on rat fr/fr colons revealed reduced numbers of crypt and goblet cells, and local angiodysplasia, as compared with heterozygous (fr/+) and wildtype littermates. Following 2% DSS treatment for 7 days followed by 7 days recovery, fr/fr animals lost body weight, and reached maximal diarrhea score and highest disease activity after only 3 days, and strongly increased cytokine levels. The histology score significantly increased in all groups, but fr/fr colons further displayed pronounced histological alterations with near absence of goblet cells, rearrangement of the lamina propria, and presence of neutrophils, eosinophils, and macrophages. Additionally, fr/fr colons showed ulcerations and edemas that were absent in fr/+ and wildtype littermates. Following recovery, fr/fr rats reached, although significantly delayed, near-normal diarrhea score and disease activity, but exhibited severe architectural remodeling, despite unchanged sodium transporter protein expression. CONCLUSIONS: In summary, our results demonstrate a protective role of colonic prostasin expression against experimental colitis, and thus represent a susceptibility gene in the development of inflammatory bowel disease.

Myoepithelioma of the parotid gland with extensive adipocytic metaplasia: Report of a case with intriguing aspects on fine needle aspiration and p63 immunohistochemical expression.

Myoepithelioma is a rare and usually benign salivary gland tumor derived from myoepithelial cells. Variability in cellular morphology and stromal composition leads to diagnostic pitfalls on fine-needle aspiration cytology; therefore, histology and immunohistochemistry are often required for definitive diagnosis. We describe a case of parotid gland myoepithelioma in a 76-year-old woman, which was discovered incidentally on cerebral magnetic resonance imaging. Fine-needle aspiration sampled cohesive aggregates of spindle-shaped cells embedded in a fibrillary matrix as well as abundant mature adipocytes, initially considered as part of normal salivary gland parenchyma. Histology of the resected specimen showed bundles of spindle-shaped cells embedded in loose connective tissue, admixed with numerous intralesional adipocytes. Immunohistochemical studies revealed a diffuse expression of p63 by this adipocytic population, an observation clearly indicating that myoepithelial cells can trans-differentiate and acquire the morphology of mature adipocytes. Knowledge of this phenomenon can be helpful in the work-up of salivary gland lesions. Diagn. Cytopathol. 2016;44:1090-1093. © 2016 Wiley Periodicals, Inc.

Hürthle Cells Adenoma of the Thyroid with Post-surgical Implants in the Neck: Clinical, Morphological, and Molecular Analysis of Three Cases.

Thyroid implants in the soft tissue of the neck are very rare findings of traumatic, iatrogenic, or neoplastic origins. We describe the clinico-pathological and molecular analysis of three cases with an initial diagnosis of follicular adenoma, Hürthle cell variant (FA-HCT), which developed cervical thyroid implants at 60, 59, and 36 months after thyroid surgery, followed by further neck recurrences, and, eventually, by distant metastases. A systematic review of all histopathological samples of both the primary lesions and the neck implants was performed. Molecular study included the analysis of pan-RAS and BRAF mutations and RET/PTC1, RET/PTC3, and PAX8/PPARγ rearrangements. The review of the original slides and of additional re-cuts of each block of the thyroid lesions did not show any sign of capsular and/or vascular invasion; thus, the original diagnoses of FA-HCT were confirmed. When sampling adequacy was considered, it turned out that the capsule was completely evaluable in case #3, whereas 85 % was evaluable for case #1 and less than 50 % for case #2. We cannot exclude that cases #1 and #2 were carcinomas that had not been completely sampled. The first occurring neck implants showed neither histological signs of malignancy nor the presence of lymphoid tissue. However, further neck recurrences had different histological aspects, with a clear infiltrative growth. Moreover, a mesenchymal reaction forming a sort of capsule was observed around oncocytic cells along with signs of vascular invasion. Molecular analysis revealed no alterations in the genes and rearrangements studied. Oncocytic thyroid implants in the neck soft tissue should be regarded as metastasis, even in the absence of clear-cut signs of malignancy and in the case of a bona fide diagnosis of Hürthle cells adenoma of the thyroid.

Acute pulmonary hypertension caused by tumor embolism: a report of two cases.

Acute pulmonary hypertension leading to right ventricular failure and circulatory collapse is usually caused by thromboembolic obstruction of the pulmonary circulation. However, in rare instances, other causes can be associated with a similar clinical presentation. We present and discuss the clinical histories of two patients with acute right ventricular failure due to an atypical cause of pulmonary hypertension, disseminated pulmonary tumor embolism.

Granulomatous Reaction to Pneumocystis jirovecii Diagnosed in a Bronchoalveolar Lavage: A Case Report.

BACKGROUND: Granulomatous reaction to Pneumocystis jirovecii is a rare but well-known pathological finding encountered in the setting of immunosuppression, HIV infection being the most common cause. It can also potentially complicate the treatment of hematological malignancies, typically when drugs lowering the count and function of lymphocytes are used. Lung biopsy is considered the gold standard for the diagnosis of granulomatous P. jirovecii pneumonia, whereas the diffuse alveolar form is usually detected cytologically in bronchoalveolar lavage (BAL). CASE: A female patient pursuing R-CHOP chemotherapy for the treatment of multiple hematological malignancies developed a rapidly progressing dyspnea. Chest CT scans revealed a worsening of a known infiltrative lung disease thought to be secondary to her chemotherapy. Alterations compatible with a drug-induced interstitial lung disease and well-formed focally necrotizing granulomas were observed on an open lung biopsy, but no microorganism was identified with special stains. Eventually, a granulomatous reaction to P. jirovecii was found in a BAL and allowed appropriate treatment with rapid improvement of the dyspnea. CONCLUSION: Because granulomas are tissue-bound structures, they are rarely described in BAL. This article describes the first reported cytological diagnosis of a granulomatous reaction to P. jirovecii and the potential diagnostic interest of such a peculiar finding.

Time-dependent specificity of immunopathologic (C4d-CD68) and histologic criteria of antibody-mediated rejection for donor-specific antibodies and allograft dysfunction in heart transplantation.

BACKGROUND: In heart transplantation, antibody-mediated rejection (AMR) is diagnosed and graded on the basis of immunopathologic (C4d-CD68) and histopathologic criteria found on endomyocardial biopsies (EMB). Because some pathologic AMR (pAMR) grades may be associated with clinical AMR, and because humoral responses may be affected by the intensity of immunosuppression during the first posttransplantation year, we investigated the incidence and positive predictive values (PPV) of C4d-CD68 and pAMR grades for clinical AMR as a function of time. METHODS: All 564 EMB from 40 adult heart recipients were graded for pAMR during the first posttransplantation year. Clinical AMR was diagnosed by simultaneous occurrence of pAMR on EMB, donor specific antibodies and allograft dysfunction. RESULTS: One patient demonstrated clinical AMR at postoperative day 7 and one at 6 months (1-year incidence 5%). C4d-CD68 was found on 4,7% EMB with a "decrescendo" pattern over time (7% during the first 4 months vs. 1.2% during the last 8 months; P < 0.05). Histopathologic criteria of AMR occurred on 10.3% EMB with no particular time pattern. Only the infrequent (1.4%) pAMR2 grade (simultaneous histopathologic and immunopathologic markers) was predictive for clinical AMR, particularly after the initial postoperative period (first 4 months and last 8 months PPV = 33%-100%; P < 0.05). CONCLUSION: In the first posttransplantation year, AMR immunopathologic and histopathologic markers were relatively frequent, but only their simultaneous occurrence (pAMR2) was predictive of clinical AMR. Furthermore, posttransplantation time may modulate the occurrence of C4d-CD68 on EMB and thus the incidence of pAMR2 and its relevance to the diagnosis of clinical AMR.

Epithelial Sodium Channel-Mediated Sodium Transport Is Not Dependent on the Membrane-Bound Serine Protease CAP2/Tmprss4.

The membrane-bound serine protease CAP2/Tmprss4 has been previously identified in vitro as a positive regulator of the epithelial sodium channel (ENaC). To study its in vivo implication in ENaC-mediated sodium absorption, we generated a knockout mouse model for CAP2/Tmprss4. Mice deficient in CAP2/Tmprss4 were viable, fertile, and did not show any obvious histological abnormalities. Unexpectedly, when challenged with sodium-deficient diet, these mice did not develop any impairment in renal sodium handling as evidenced by normal plasma and urinary sodium and potassium electrolytes, as well as normal aldosterone levels. Despite minor alterations in ENaC mRNA expression, we found no evidence for altered proteolytic cleavage of ENaC subunits. In consequence, ENaC activity, as monitored by the amiloride-sensitive rectal potential difference (ΔPD), was not altered even under dietary sodium restriction. In summary, ENaC-mediated sodium balance is not affected by lack of CAP2/Tmprss4 expression and thus, does not seem to directly control ENaC expression and activity in vivo.