Synchronous Colonic Adenocarcinoma and Metastatic Lobular Carcinoma in a Colectomy Specimen: A Rare Finding

Uterine collision tumor (PEComa and endometrioid carcinoma) in a tuberous sclerosis patient: a case report

Perivascular epithelioid cell tumors are very rare mesenchymal neoplasms arising in various locations, such as the female genital tract, kidney, lung, prostate, bladder, pancreas, soft tissues, and bone. They possess a unique immunophenotype, co-expressing myogenic and melanocytic markers; molecular findings include mutations of tuberous sclerosis complex and translocations of transcription factor E3, a member of the microphthalmia transcription factor gene family. We herewith report a uterine collision tumor consisting of a perivascular epithelioid cell tumor and a moderately differentiated endometrial endometrioid carcinoma in a patient with genetically proven tuberous sclerosis; two leiomyomas were also found in contact with the tumor. Although two such cases one with a benign and another with a malignant perivascular epithelioid cell tumor have previously been reported, ours is, to our knowledge, the first reported in a tuberous sclerosis patient.

Diagnostically Challenging Subtypes of Invasive Lobular Carcinomas: How to Avoid Potential Diagnostic Pitfalls

Invasive lobular carcinoma is the most common special breast carcinoma subtype, with unique morphological (discohesive cells, single-cell files, targetoid pattern) and immunohistochemical (loss of E-cadherin and β-catenin staining) features. Moreover, ILC displays a poor response to neoadjuvant therapy, a different metastatic pattern compared to invasive breast carcinoma of no special type, as well as unique molecular characteristics. In addition to the classic variant of invasive lobular carcinoma, several other well-recognized variants exist, including classic, alveolar, tubulolobular, solid, pleomorphic, signet-ring, and mixed. Furthermore, three novel variants of invasive lobular carcinoma, i.e., with extracellular mucin production, papillary features, and tubular elements, have been described during the last decade. We herewith focus on the unique morphological and immunohistochemical characteristics of these novel varieties of invasive lobular carcinoma, as well as differential diagnostic considerations and potential diagnostic pitfalls, especially when dealing with biopsy specimens.

Lobular Mammary Carcinoma Presenting as an Obstructing Rectal Mass

Breast cancer is the leading cause of cancer death in women, and while metastasis is common to areas like the bone, lungs, and brain, it is rare to metastasize to the gastrointestinal tract and especially to the rectum. Due to the rarity of this condition and its resemblance clinically and radiologically to primary gastrointestinal tract tumors, diagnosis and treatment are challenging. We present a case of metastatic lobular mammary carcinoma in a 52-year-old Bahraini woman who presented with an obstructing rectal mass.

The Rare Diagnosis of Synchronous Breast and Colonic Cancers: A Case Report and Review of Literature

Any two or more primary malignant tumors, in which each tumor is not an extension, recurrence, or metastasis of the other lesion, are defined or described as multiple primary malignant neoplasms (MPMN). These tumors are increasingly diagnosed despite their rare occurrence rate. The term synchronous tumors is applied if two different tumors originating in the same patient are detected at the same time or within six months; if the second tumor is detected beyond six months, it is called metachronous. Aetiological factors that may predispose patients to MPMNs have been grouped into three broad categories: familial cancer syndromes and other genetic susceptibility factors, common exposures (e.g. tobacco), and carcinogenic effects of cancer treatment. The likelihood of missing asymptomatic synchronous tumors at the time of diagnosis is due to a lack of definitively set guidelines for synchronous tumors. Studying every individual case may aid us in understanding disease biology, developing diagnostic guidelines, and establishing patient-specific management strategies. We present a case report of synchronous breast and colonic cancer in a female patient.

Invasive Lobular Carcinoma with Extracellular Mucin Production: Description of a Case and Review of the Literature

Invasive lobular carcinoma of the breast is the second most common subtype of breast carcinoma. It accounts for 5-15% of the breast carcinoma cases reported. It shows a different metastatic pattern compared to invasive carcinoma of no special type. There are several variants of this cancer including the classic, solid, signet ring cell, tubulolobular, alveolar, trabecular, pleomorphic, and mixed subtypes each one with a distinctive morphology. Invasive lobular carcinoma has been associated with intracellular mucin production, in the form of intracytoplasmic lumina and signet ring cells whereas extracellular mucin production has been related to carcinomas of ductal origin. A new variant that displays extracellular mucin production was described recently. Only nineteen cases of this rare entity have been reported to date. In this manuscript, we report an additional case of invasive lobular carcinoma with extracellular mucin production, describing its clinico-pathological characteristics, and review the literature on the same.