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Case Report
Idiopathic calcinosis cutis with unusual histomorphology and negative von Kossa stain: A diagnostic pitfall
1 MD, Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
2 MD, MPH, Division of Dermatology, Department of Medicine, University of Washington, Seattle, Washington, USA
Address correspondence to:
Trent Irwin
MD, 1959 NE Pacific St., Seattle, WA 98195,
USA
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Article ID: 100067Z11TI2023
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Irwin T, Hamza M, George E, Moshiri AS. Idiopathic calcinosis cutis with unusual histomorphology and negative von Kossa stain: A diagnostic pitfall. J Case Rep Images Pathol 2023;9(1):1–6.ABSTRACT
Introduction: Calcinosis cutis is characterized by basophilic crystalline or amorphous calcium within the dermis/subcutis. Calcinosis cutis has many different clinical subtypes and associated etiologies that may lead clinicians to consider this diagnosis. Von Kossa and/or Alizarin red special stains may be used by pathologists to highlight deposition of insoluble calcium salts, especially in histologically ambiguous or subtle cases.
Case Report: We report the case of a 27-year-old male who presented with an inferior right buttock mass clinically diagnosed as epidermal inclusion cyst(s). Gross pathology revealed a gray-white pasty substance within a cyst-like structure. Histopathologic examination demonstrated pools of amorphous blue-gray material with rare deposits of admixed coarse calcifications surrounded by foreign-body giant cells. No cyst wall was seen in the specimen. Special stains, including von Kossa, were initially negative. Following additional review, it was discovered that surface decalcifying solution had been applied to the paraffin block in the histology lab prior to microtome sectioning. Hypothesizing that this could be the cause of the unusual morphology, the paraffin block was reprocessed and subsequent H&E stained sections displayed characteristic basophilic calcium deposits, which were correspondingly positive by von Kossa stain.
Conclusion: The histopathologic diagnosis of calcinosis cutis is apparent by H&E in most cases, though von Kossa and/or Alizarin red special stains can be used to aid the pathologist. Given the unusual histomorphology following surface decalcification and initial lack of von Kossa stain prior to reprocessing, this report serves to make pathologists aware of this potential diagnostic pitfall.
Keywords: Calcinosis cutis, Histomorphology, von Kossa
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Author Contributions
Trent Irwin - Conception of the work, Design of the work, Acquisition of data, Analysis of data, Drafting the work, Final approval of the version to be published, Agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Mugahed Hamza - Conception of the work, Design of the work, Drafting the work, Revising the work critically for important intellectual content, Final approval of the version to be published, Agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Evan George - Conception of the work, Design of the work, Acquisition of data, Analysis of data, Drafting the work, Revising the work critically for important intellectual content, Final approval of the version to be published, Agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Ata S Moshiri - Conception of the work, Design of the work, Acquisition of data, Analysis of data, Drafting the work, Revising the work critically for important intellectual content, Final approval of the version to be published, Agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Guarantor of SubmissionThe corresponding author is the guarantor of submission.
Source of SupportNone
Consent StatementWritten informed consent was obtained from the patient for publication of this article.
Data AvailabilityAll relevant data are within the paper and its Supporting Information files.
Conflict of InterestAuthors declare no conflict of interest.
Copyright© 2023 Trent Irwin et al. This article is distributed under the terms of Creative Commons Attribution License which permits unrestricted use, distribution and reproduction in any medium provided the original author(s) and original publisher are properly credited. Please see the copyright policy on the journal website for more information.
