Advancing the PD-L1 CPS test in metastatic TNBC: Insights from pathologists and findings from a nationwide survey.

Pembrolizumab has received approval as a first-line treatment for unresectable/metastatic triple-negative breast cancer (mTNBC) with a PD-L1 combined positive score (CPS) of ≥ 10. However, assessing CPS in mTNBC poses challenges. Firstly, it represents a novel analysis for breast pathologists. Secondly, the heterogeneity of PD-L1 expression in mTNBC further complicates the assessment. Lastly, the lack of standardized assays and staining platforms adds to the complexity. In KEYNOTE trials, PD-L1 expression was evaluated using the IHC 22C3 pharmDx kit as a companion diagnostic test. However, both the 22C3 pharmDx and VENTANA PD-L1 (SP263) assays are validated for CPS assessment. Consequently, assay-platform choice, staining conditions, and scoring methods can significantly impact the testing outcomes. This consensus paper aims to discuss the intricacies of PD-L1 CPS testing in mTNBC and provide practical recommendations for pathologists. Additionally, we present findings from a nationwide Italian survey elucidating the state-of-the-art in PD-L1 CPS testing in mTNBC.

A Rare Case of Negative Serum Calcitonin in Metastatic Medullary Thyroid Carcinoma: Diagnosis, Treatment, and Follow-Up Strategy.

BACKGROUND Medullary thyroid carcinoma is a rare tumor and represents less than 5% of all thyroid cancers. Tumor size and the presence of possible metastases are strictly related to serum calcitonin level, which also suggests prognosis. A serum calcitonin level above the normal range is highly suspicious for medullary cancer. This tumor has no characteristic patterns on ultrasound and fine-needle aspiration, so serum calcitonin level is the only significant element for diagnosis. The literature contains 47 cases of serum calcitonin-negative medullary thyroid cancer with heterogeneous behavior, ranging from non-aggressive to aggressive form. CASE REPORT We report a rare case of a young man with negative serum calcitonin but with lateral cervical node metastases from medullary thyroid carcinoma. At the beginning, diagnosis was not achieved due to normal range of serum calcitonin and a negative thyroid ultrasonography for large nodules. Nevertheless, in another medical center he underwent a neck biopsy of the lateral cervical mass. The histologic findings showed metastases of medullary thyroid cancer. Therefore, a total thyroidectomy plus cervical lymphadenectomy was performed. During the follow-up, due to unusefulness of serum markers, and as CEA levels were negative pre- and post-operatively, an ¹8F-DOPA PET scan was performed. In 3 years of follow-up, there is still no evidence of disease relapse. CONCLUSIONS Our case shows how a normal serum level of calcitonin cannot exclude medullary thyroid cancer. Early diagnosis is crucial because it influences appropriate surgical therapy and patient outcome. The current lack of an optimal strategy for the diagnosis and postoperative follow-up for patients with negative serum calcitonin tumor presents a diagnostic challenge for physicians.

Intraparotid Osteolipoma: Treatment Option and Surgical View.

ABSTRACT: Osteolipoma is a benign neoplasm originating from the mesenchymal fat tissue cells and characterized by the presence of bone formation. In the head and neck district osteolipoma has been described as parapharyngeal, nasopharinx, submandibular gland, eyelid, floor of the mouth, and skull base lesion. Only 1 case of osteolipoma was reported as a neoplasm of the parotid region. Considering the rarity of the osteolipoma, our purpose was to describe the first case of totally intraparotid gland localization of osteolipoma and summarize and review the actual literature concerning the presence of this tumor in the region of major salivary glands. A 56-years-old male patient was treated for intraparotid osteolipoma. Surgical removal of tumor was done with a standard preauricular/cervical incision and blunt dissection. The facial nerve was identified and preserved completely. In the reviewed series, all cases were reported in adult patients with a relative long history of slow progression. According to our paper and the review of the literature, we can assess that Osteolipoma is an extremely rare lesion affecting the major salivary glands, which should be considered along with common salivary gland tumors in the differential diagnosis.

Unclassified pediatric renal stromal tumor overlapping with metanephric stromal tumor and solitary fibrous tumor with diffuse S-100 protein expression.

Metanephric stromal tumor (MST) is a rare pediatric neoplasm unique to the kidneys that is currently included in the spectrum of metanephric tumors, along with metanephric adenoma and adenofibroma. We herein report an unusual case of pediatric renal stromal tumor overlapping with MST and solitary fibrous tumor (SFT). Histologically, the tumor was composed of bland-looking spindle to stellate cells embedded in a fibro-sclerotic stroma that focally surrounded native entrapped renal tubules or blood vessels with abortive rings or collarettes. Alternating hypercellular and hypocellular areas and a focal hemangiopericytomatous-like vascular pattern imparted to the tumor a resemblance to SFT. Angiodysplasia of intratumoral arterioles was also observed, but juxtaglomerular cell hyperplasia was not a feature. Immunohistochemically, the neoplastic cells showed a polyphenotypic profile, including diffuse expression of vimentin and CD34, and focal immunoreactivity for alpha-smooth muscle actin, EMA, and CD99. However, the most striking finding was diffuse nuclear and cytoplasmic expression of S-100 protein. Although this protein has been reported to stain the heterologous glial and/or cartilaginous components that can be occasionally encountered in MST, this marker has not been previously reported in the fibroblastic component of MST. Pathologist should be aware of similar unusual unclassified tumors to avoid potential confusion with other benign or malignant S-100 protein-positive tumors.

Biliary adenofibroma of the liver: report of a case and review of the literature.

We herein report the clinicopathologic features of a rare case of biliary adenofibroma (BAF) of the liver in a 79-year-old man. Grossly, tumour presented as a well-circumscribed, 5.5-cm mass with a solid and microcystic appearance. Histological examination was typical of biliary adenofibroma, showing a proliferation of variable-sized tubulocystic structures embedded in a moderately cellular fibrous stroma. Immunohistochemistry, revealing immunoreactivity of the epithelial component to cytokeratins 7 and 19, was consistent with a bile duct origin. Notably, the stromal cells had a myofibroblastic profile, showing a diffuse and strong expression of vimentin and α-smooth muscle actin. Differential diagnosis with Von Meyenburg complex, biliary adenoma, biliary cistadenoma, congenital biliary cystsy, and hepatic benign cystic mesothelioma is provided. The occasionally reported expression of p53 in biliary adenofibroma has suggested that this tumour could represent a premalignant lesion. The absence of both cytological atypia and p53 immunoreactivity in our case confirms that BAF is a benign tumour with an indolent clinical behaviour. However, a careful histological examination of BAF is mandatory because malignant transformation of the epithelial component has been documented in two cases.

Incompletely differentiated (unclassified) sex cord/gonadal stromal tumor of the testis with a "pure" spindle cell component: report of a case with diagnostic and histogenetic considerations.

The group of incompletely differentiated (unclassified) sex cord/gonadal stromal tumors includes rare cases with predominant spindle cell morphology. We report a rare case of a "pure" spindle cell tumor of the testis with morphological and immunohistochemical features consistent with the diagnosis of "incompletely differentiated sex cord/gonadal stromal tumor". Given the spindle cell morphology, the differential diagnosis with other benign and malignant spindle cell lesions is discussed. The concurrent presence of some morphological and immunohistochemical features of both Leydig and granulosa cell lines in the tumor suggests its origin from a stromal stem cell, possibly capable of dual differentiation, but with an arrest of maturation at an early phase of differentiation.