OBJECTIVE: Superficial CD34-positive fibroblastic tumour (SCD34FT) is an uncommon but distinctive low-grade neoplasm of the skin and subcutis that shows frequent CADM3 expression by immunohistochemistry (IHC). In this study, prompted by an index case resembling \'atypical fibrous histiocytoma (FH)\' that was positive for CADM3 IHC, we systematically examined a cohort of tumours previously diagnosed as \'atypical FH\' by applying CADM3 and fluorescence in situ hybridization (FISH) for PRDM10 rearrangement, to investigate the overlap between these tumour types.
RESULTS: Forty cases of atypical FH were retrieved, including CD34-positive tumours (n = 20) and CD34-negative tumours (n = 20). All tumours were stained for CADM3. All CADM3-positive tumours were evaluated by FISH to assess for PRDM10 rearrangement. Eleven CD34-positive tumours (11/20, 55%) coexpressed CADM3 and were reclassified as SCD34FT. None (0/20) of the CD34-negative atypical FH were CADM3-positive. Reclassified SCD34FT (10/11) arose on the lower extremity, with frequent involvement of the thigh (n = 8). Features suggestive of atypical FH were observed in many reclassified cases including variable cellularity, spindled morphology, infiltrative tumour margins, collagen entrapment, epidermal hyperpigmentation, and acanthosis. Variably prominent multinucleate giant cells, including Touton-like forms, were also present. An informative FISH result was obtained in 10/11 reclassified tumours, with 60% (6/10) demonstrating PRDM10 rearrangement.
CONCLUSIONS: A significant subset of tumours that histologically resemble atypical FH, and are positive for CD34, coexpress CADM3 and harbour PRDM10 rearrangement, supporting their reclassification as SCD34FT. Awareness of this morphologic overlap and the application of CADM3 IHC can aid the distinction between SCD34FT and atypical FH.

The primary aim of this study was to determine the upgrade rates of variant lobular carcinoma in situ (V-LCIS, ie, combined florid [F-LCIS] and pleomorphic [P-LCIS]) compared with classic LCIS (C-LCIS) when diagnosed on core needle biopsy (CNB). The secondary goal was to determine the rate of progression/development of invasive carcinoma on long-term follow-up after primary excision. After institutional review board approval, our institutional pathology database was searched for patients with \"pure\" LCIS diagnosed on CNB who underwent subsequent excision. Radiologic findings were reviewed, radiologic-pathologic (rad-path) correlation was performed, and follow-up patient outcome data were obtained. One hundred twenty cases of LCIS were identified on CNB (C-LCIS = 97, F-LCIS = 18, and P-LCIS = 5). Overall upgrade rates after excision for C-LCIS, F-LCIS, and P-LCIS were 14% (14/97), 44% (8/18), and 40% (2/5), respectively. Of the total cases, 79 (66%) were deemed rad-path concordant. Of these, the upgrade rate after excision for C-LCIS, F-LCIS, and P-LCIS was 7.5% (5 of 66), 40% (4 of 10), and 0% (0 of 3), respectively. The overall upgrade rate for V-LCIS was higher than for C-LCIS (P = .004), even for the cases deemed rad-path concordant (P value: .036). Most upgraded cases (23 of 24) showed pT1a disease or lower. With an average follow-up of 83 months, invasive carcinoma in the ipsilateral breast was identified in 8/120 (7%) cases. Six patients had died: 2 of (contralateral) breast cancer and 4 of other causes. Because of a high upgrade rate, V-LCIS diagnosed on CNB should always be excised. The upgrade rate for C-LCIS (even when rad-path concordant) is higher than reported in many other studies. Rad-path concordance read, surgical consultation, and individualized decision making are recommended for C-LCIS cases. The risk of developing invasive carcinoma after LCIS diagnosis is small (7% with ∼7-year follow-up), but active surveillance is required to diagnose early-stage disease.

Pleomorphic liposarcoma (PLPS) is the least common but most aggressive of all forms of liposarcoma (LPS). Its diagnosis relies on the recognition of pleomorphic lipoblasts (PLBs), whose numbers vary considerably. Because few large fine-needle aspiration (FNA) biopsy studies exist, the authors review their experience with PLPS.
The authors\' cytopathology files were searched for PLPS with histopathologic verification. FNA biopsy smears were performed via standard techniques.
Twenty cases from 20 patients (male/female ratio, 2.3/1; age range, 22-77 years; mean age, 58 years) met the inclusion criteria. All had tissue confirmation. Biopsy sites included the following: thigh (11 [55%]), upper extremity (4 [20%]), axilla (2 [10%]), neck (1 [5%]), chest wall (1 [5%]), and mediastinum (1 [5%]). Aspirates were from primary (17 [85%]), locally recurrent (2 [10%]), and metastatic neoplasms (1 [5%]). The FNA diagnoses were PLPS (10 [50%]), myxofibrosarcoma (4 [20%]), LPS (2 [10%]), sarcoma (2 [10%]), and high-grade malignant neoplasm (2 [10%]). Smears showed thick cell clusters and dissociated single forms. Pleomorphic, epithelioid, and bizarre cell/nuclear shapes were common. PLBs were absent, rare, or unnoticed in 45%. In 25%, smears dominated by myxoid stroma were diagnosed as high-grade myxofibrosarcoma or myxoid LPS. Ancillary testing performed in 5 cases had limited diagnostic efficacy.
FNA biopsy of PLPS, although able to successfully recognize malignancy, suffers from a sampling bias due to an inability to capture or recognize PLBs in a significant proportion of cases secondary to the heterogeneous composition of this neoplasm.

UNASSIGNED: Pleomorphic carcinoma of the lung is a rare malignant epithelial tumor. Due to its rarity, its clinicopathological characteristics are not clear, and there is no defined therapeutic path for this type of tumor.
METHODS: We retrospectively analyzed the medical and pathological reports of 8 patients who underwent surgical resection for pleomorphic carcinoma between 2007 and 2010.
UNASSIGNED: Eight patients were analyzed (7 males and 1 female, mean age 60). All patients underwent CT scans, and the average diameter of the nodules was 56 mm. Four patients were also investigated with FDG-PET with hypermetabolic activity in all four cases. In four patients, the carcinomatous component was adenocarcinoma (all with sarcomatoid component of spindle cell and giant cell carcinoma), although in two patients, it was squamous cell carcinoma (one with spindle cell and one with giant cell). In the two remaining patients, one showed a non-small cell carcinoma with giant cell carcinoma, and the other was a non-small cell carcinoma and squamous cell carcinoma with spindle and giant cell carcinoma. All cases were treated with surgical resection. Only two patients underwent neoadjuvant chemotherapy. At the time of data analysis, only one patient treated with neoadjuvant chemotherapy was alive.
CONCLUSIONS: The prognosis for these patients with a diagnosis of pleomorphic carcinoma undergoing surgery is generally better than those not treated with surgical resection, however the survival remains poor. Although with low number of patients, our research would suggest to consider neoadjuvant chemotherapy an appropriate approach for improving the outcomes before surgery.

Our purpose is to evaluate the performance of magnetic resonance (MR) radiomics analysis for differentiating between malignant and benign parotid neoplasms and, among the latter, between pleomorphic adenomas and Warthin tumors. We retrospectively evaluated 75 T2-weighted images of parotid gland lesions, of which 61 were benign tumors (32 pleomorphic adenomas, 23 Warthin tumors and 6 oncocytomas) and 14 were malignant tumors. A receiver operating characteristics (ROC) curve analysis was performed to find the threshold values for the most discriminative features and determine their sensitivity, specificity and area under the ROC curve (AUROC). The most discriminative features were used to train a support vector machine classifier. The best classification performance was obtained by comparing a pleomorphic adenoma with a Warthin tumor (yielding sensitivity, specificity and a diagnostic accuracy as high as 0.8695, 0.9062 and 0.8909, respectively) and a pleomorphic adenoma with malignant tumors (sensitivity, specificity and a diagnostic accuracy of 0.6666, 0.8709 and 0.8043, respectively). Radiomics analysis of parotid tumors on conventional T2-weighted MR images allows the discrimination of pleomorphic adenomas from Warthin tumors and malignant tumors with a high sensitivity, specificity and diagnostic accuracy.

Aggressive morphologic variants of mantle cell lymphoma (MCL), including blastoid and pleomorphic (B/P-MCL), are rare and associated with poor clinical outcomes. The genomic landscape of these variants remains incompletely explored. In this multi-institutional study, we describe recurrent mutations and novel genomic copy number alterations (CNAs) in B/P-MCL, using next generation sequencing and SNP-array. Chromothripsis, a recently described phenomenon of massive chromosomal rearrangements, was identified in eight of 13 (62%) B/P MCL cases, and a high degree of genomic complexity with frequent copy number gains and losses was also seen. In contrast, a comparative cohort of nine cases of conventional MCL (C-MCL) showed no chromothripsis and less complexity. Twelve of 13 (92%) B/P-MCL cases showed loss of CDKN2A/B (6 biallelic and 6 monoallelic losses); while only one C-MCL showed monoallelic CDKN2A/B loss. In B/P-MCL, TP53 was the most commonly mutated gene, with mutations present in eight cases (62%), six of which showed concurrent loss of chromosome 17p. Of the eight cases with chromothripsis, six (85%) harbored TP53 mutations. Other recurrent mutations in B/P-MCL included ATM (7, 53%), CCND1 (5, 38%), NOTCH1 (2, 18%), NOTCH2, and BIRC3 (each in 3, 23%). Here, we describe high genomic instability associated with chromothripsis and a high frequency of CDKN2A/B and TP53 alterations in the aggressive variants of MCL. The nonrandom chromothripsis events observed in B/P-MCL may be an indicator of clinically aggressive MCL. In addition, frequent CDKN2A deletion and high genomic instability may provide potential targets for alternative treatment.